Spheroid Mass Research Articles

A polo ball in the right atrium, importance of echocardiographic characteristics of intracardiac myxomas: a case report

BackgroundMyxomas are the most prevalent type of heart tumors, mainly occurring in the left atrium, with approximately 20% of cases found in the right atrium. Timely diagnosis and appropriate management of myxomas are crucial for favorable outcomes and to minimize complications.Case presentationA 77-year-old Asian male with no significant medical history presented with intermittent trepopnea and palpitations. Physical examination revealed regular heart sounds and no other relevant findings. A transthoracic echocardiogram showed a large, round-shaped, smooth-edged mass with diameter of 86 mm, occupying most of the right atrium. Mild tricuspid flow obstruction and mild left ventricular systolic dysfunction were also observed. Cardiac tomography confirmed the size, smooth edges, and showed microcalcifications of the mass, with no invasion of surrounding tissues. Surgical intervention successfully removed the spheroid mass, leading to the alleviation of symptoms. Histopathology confirmed the myxoma nature of the mass. A comprehensive discussion based on relevant medical literature is provided, with emphasis on echocardiographic characteristics of the mass with relation to potential embolic disease.ConclusionThis case shows an atypical presentation of an exceptionally large myxoma in the right atrium, resembling the size of a polo ball, in a patient presenting with supraventricular arrhythmia and trepopnea. Early diagnosis and appropriate management played a vital role in achieving a successful outcome for the patient.

CD271 activation prevents low to high-risk progression of cutaneous squamous cell carcinoma and improves therapy outcomes

BackgroundCutaneous squamous cell carcinoma (cSCC) is the second most prevalent form of skin cancer, showing a rapid increasing incidence worldwide. Although most cSCC can be cured by surgery, a sizeable number of cases are diagnosed at advanced stages, with local invasion and distant metastatic lesions. In the skin, neurotrophins (NTs) and their receptors (CD271 and Trk) form a complex network regulating epidermal homeostasis. Recently, several works suggested a significant implication of NT receptors in cancer. However, CD271 functions in epithelial tumors are controversial and its precise role in cSCC is still to be defined.MethodsSpheroids from cSCC patients with low-risk (In situ or Well-Differentiated cSCC) or high-risk tumors (Moderately/Poorly Differentiated cSCC), were established to explore histological features, proliferation, invasion abilities, and molecular pathways modulated in response to CD271 overexpression or activation in vitro. The effect of CD271 activities on the response to therapeutics was also investigated. The impact on the metastatic process and inflammation was explored in vivo and in vitro, by using zebrafish xenograft and 2D/3D models.ResultsOur data proved that CD271 is upregulated in Well-Differentiated tumors as compared to the more aggressive Moderately/Poorly Differentiated cSCC, both in vivo and in vitro. We demonstrated that CD271 activities reduce proliferation and malignancy marker expression in patient-derived cSCC spheroids at each tumor grade, by increasing neoplastic cell differentiation. CD271 overexpression significantly increases cSCC spheroid mass density, while it reduces their weight and diameter, and promotes a major fold-enrichment in differentiation and keratinization genes. Moreover, both CD271 overexpression and activation decrease cSCC cell invasiveness in vitro. A significant inhibition of the metastatic process by CD271 was observed in a newly established zebrafish cSCC model. We found that the recruitment of leucocytes by CD271-overexpressing cells directly correlates with tumor killing and this finding was further highlighted by monocyte infiltration in a THP-1-SCC13 3D model. Finally, CD271 activity synergizes with Trk receptor inhibition, by reducing spheroid viability, and significantly improves the outcome of photodynamic therapy (PTD) or chemotherapy in spheroids and zebrafish.ConclusionOur study provides evidence that CD271 could prevent the switch between low to high-risk cSCC tumors. Because CD271 contributes to maintaining active differentiative paths and favors the response to therapies, it might be a promising target for future pharmaceutical development.

MIRI/JWST observations reveal an extremely obscured starburst in the z = 6.9 system SPT0311-58

Luminous infrared starbursts in the early Universe are thought to be the progenitors of massive quiescent galaxies identified at redshifts 2–4. Using the Mid-IRfrared Instrument (MIRI) on board the James Webb Space Telescope (JWST), we present mid-infrared sub-arcsec imaging and spectroscopy of such a starburst: the slightly lensed hyper-luminous infrared system SPT0311-58 at z = 6.9. The MIRI IMager (MIRIM) and Medium Resolution Spectrometer (MRS) observations target the stellar (rest-frame 1.26 μm emission) structure and ionised (Paα and Hα) medium on kpc scales in the system. The MIRI observations are compared with existing ALMA far-infrared continuum and [C II]158μm imaging at a similar angular resolution. Even though the ALMA observations imply very high star formation rates (SFRs) in the eastern (E) and western (W) galaxies of the system, the Hα line is, strikingly, not detected in our MRS observations. This fact, together with the detection of the ionised gas phase in Paα, implies very high internal nebular extinction with lower limits (AV) of 4.2 (E) and 3.9 mag (W) as well as even larger values (5.6 (E) and 10.0 (W)) by spectral energy distribution (SED) fitting analysis. The extinction-corrected Paα lower limits of the SFRs are 383 and 230 M⊙ yr−1 for the E and W galaxies, respectively. This represents 50% of the SFRs derived from the [C II]158 μm line and infrared light for the E galaxy and as low as 6% for the W galaxy. The MIRIM observations reveal a clumpy stellar structure, with each clump having 3–5×109 M⊙ mass in stars, leading to a total stellar mass of 2.0 and 1.5×1010 M⊙ for the E and W galaxies, respectively. The specific star formation (sSFR) in the stellar clumps ranges from 25 to 59 Gyr−1, assuming a star formation with a 50–100 Myr constant rate. This sSFR is three to ten times larger than the values measured in galaxies of similar stellar mass at redshifts 6–8. Thus, SPT0311-58 clearly stands out as a starburst system when compared with typical massive star-forming galaxies at similar high redshifts. The overall gas mass fraction is Mgas/M* ∼ 3, similar to that of z ∼ 4.5–6 star-forming galaxies, suggesting a flattening of the gas mass fraction in massive starbursts up to redshift 7. The kinematics of the ionised gas in the E galaxy agrees with the known [C II] gas kinematics, indicating a physical association between the ionised gas and the cold ionised or neutral gas clumps. The situation in the W galaxy is more complex, as it appears to be a velocity offset by about +700 km s−1 in the Paα relative to the [C II] emitting gas. The nature of this offset and its reality are not fully established and require further investigation. The observed properties of SPT0311-58, such as the clumpy distribution at sub(kpc) scales and the very high average extinction, are similar to those observed in low- and intermediate-z luminous (E galaxy) and ultra-luminous (W galaxy) infrared galaxies, even though SPT0311-58 is observed only ∼800 Myr after the Big Bang. Such massive, heavily obscured clumpy starburst systems as SPT0311-58 likely represent the early phases in the formation of a massive high-redshift bulge, spheroids and/or luminous quasars. This study demonstrates that MIRI and JWST are, for the first time, able to explore the rest-frame near-infrared stellar and ionised gas structure of these galaxies, even during the Epoch of Reionization.

Disc cloaking: Establishing a lower limit to the number density of local compact massive spheroids/bulges and the potential fate of some high-z red nuggets

ABSTRACT The near-absence of compact massive quiescent galaxies in the local Universe implies a size evolution since z ∼ 2.5. It is often theorized that such ‘red nuggets’ have evolved into today’s elliptical (E) galaxies via an E-to-E transformation. We examine an alternative scenario in which a red nugget develops a rotational disc through mergers and accretion, say, at 1 ≲ z ≲ 2, thereby cloaking the nugget as the extant bulge/spheroid component of a larger, now old, galaxy. We have performed detailed, physically motivated, multicomponent decompositions of a volume-limited sample of 103 massive ($M_*/\rm M_{\odot } \gtrsim 1\times 10^{11}$) galaxies within 110 Mpc. Many less massive nearby galaxies are known to be ‘fast-rotators’ with discs. Among our 28 galaxies with existing elliptical classifications, we found that 18 have large-scale discs, and two have intermediate-scale discs, and are reclassified here as lenticulars (S0) and elliculars (ES). The local spheroid stellar mass function, size–mass diagram and bulge-to-total (B/T) flux ratio are presented. We report lower limits for the volume number density of compact massive spheroids, nc, Sph ∼ (0.17–$1.2) \times 10^{-4}\, \rm Mpc^{-3}$, based on different definitions of ‘red nuggets’ in the literature. Similar number densities of local compact massive bulges were reported by de la Rosa et al. using automated two-component decompositions and their existence is now abundantly clear with our multicomponent decompositions. We find disc-cloaking to be a salient alternative for galaxy evolution. In particular, instead of an E-to-E process, disc growth is the dominant evolutionary pathway for at least low-mass ($1\times 10^{10}\lt M_*/\rm M_{\odot } \lessapprox 4 \times 10^{10}$) red nuggets, while our current lower limits are within an alluring factor of a few of the peak abundance of high-mass red nuggets at 1 ≲ z ≲ 2.

Glucose Conferred Irinotecan Chemoresistance through Divergent Actions of Pyruvate and ATP in Cell Death and Proliferation of Colorectal Cancer

Altered glucose metabolism is associated with chemoresistance in colorectal cancer (CRC). This study aimed to illustrate the molecular mechanisms of glucose-mediated chemoresistance against irinotecan, a topoisomerase I inhibitor, focusing on the distinct roles of metabolites such as pyruvate and ATP in modulating cell death and proliferation. Four human CRC cell lines, tumorspheres, and mouse xenograft models were treated with various doses of irinotecan in the presence of various concentrations of glucose, pyruvate, or ATP-encapsulated liposomes. In this study, human CRC cell lines treated with irinotecan in high glucose displayed increased cell viability and larger xenograft tumor sizes in mouse models compared to those treated in normal glucose concentrations. Irinotecan induced apoptosis and necroptosis, both mitigated by high glucose. Liposomal ATP prevented irinotecan-induced apoptosis, while it did not affect necroptosis. In contrast, pyruvate attenuated the receptor-interacting protein kinase 1/3-dependent necroptosis via free radical scavenging without modulating apoptotic levels. Regarding the cell cycle, liposomal ATP aggravated the irinotecan-induced G0/G1 shift, whereas pyruvate diminished the G0/G1 shift, showing opposite effects on proliferation. Last, tumorsphere structural damage, an index of solid tumor responsiveness to chemotherapy, was determined. Liposomal ATP increased tumorsphere size while pyruvate prevented the deformation of spheroid mass. Glucose metabolites confer tumor chemoresistance via multiple modes of action. Glycolytic pyruvate attenuated irinotecan-induced necroptosis and potentiated drug insensitivity by shifting cells from a proliferative to a quiescent state. On the other hand, ATP decreased irinotecan-induced apoptosis and promoted active cell proliferation, contributing to tumor recurrence. Our findings challenged the traditional view of ATP as the main factor for irinotecan chemoresistance and provided novel insights of pyruvate acting as an antioxidant responsible for drug insensitivity, which may shed light on the development of new therapies against recalcitrant cancers.

Hyperspectral characterization of the MSTO-211H cell spheroid model: A FPA–FTIR imaging approach

Multicellular spheroids are the new frontier for studying how the tumour micro-environment interferes with drug uptake and response, since they can reproduce a three-dimensional cellular organisation mimicking the behaviour of in vivo solid tissues. In this study, we exploited Focal Plane Array - Fourier Transform Infrared Imaging spectroscopy to characterize the biochemical features, in terms of distribution and composition of the meaningful macromolecules (lipids, proteins, sugars and nucleic acids), of malignant pleural mesothelioma spheroid sections, and, as further extent, to investigate the penetrating effects of cisplatin within the spheroid mass. The hyperspectral imaging analysis evidenced, in untreated spheroids, the occurrence of a replicative outer region and a hypoxic inner one, as suggested by the band area ratios related to lipid alkyl chains (2925/2960) and glycogen (1020/1650), which showed the highest values in the inner region. Moreover, the HCA spectroscopic images showed, after cisplatin treatment, an increase of the band area ratio related to lipid carbonyl ester moiety (1740/2925), suggesting the occurrence of lipid peroxidation; furthermore, the band area ratio related to nucleic acids (1240/1220) revealed a DNA fragmentation along all regions of spheroids that may be related to apoptotic mechanisms, whereas a reduction of the band area ratios related to glycogen and carbohydrates (1020/1650 and 1054/1650, respectively) appeared consistent with an inhibition of cell division. The few spectral differences between the outer and the inner regions of cisplatin-treated spheroids pointed out the diffuse penetrating effect of the drug.

Power spectrum of intrinsic alignments of galaxies in IllustrisTNG

We present the 3-dimensional intrinsic alignment power spectra between the projected 2d galaxy shape/spin and the 3d tidal fieldacross 0.1<k/<60 using cosmological hydrodynamical simulation, Illustris-TNG300, at redshifts ranging from 0.3 to 2. The shape-tidal field alignment increases with galaxy mass and the linear alignment coefficient AIA, defined with respect to the primordial tidal field, is found to have weak redshift dependence. We also show a promising detection of the shape/spin-tidal field alignments for stellar mass limited samples and a weak or almost null signal for star-forming galaxies for the TNG300 volume, ∼ 0.01 (h-1 Gpc)3.We further study the morphology and environmental dependence of the intrinsic alignment power spectra. The shape of massive disk- and spheroid-galaxies tend to align with the tidal field. The spin of low mass disks (and spheroids at low redshifts) tend to be parallel with the tidal field, while the spin of massive spheroids and disks tend to be perpendicular to tidal field.The shape and spin of massive centrals align with the tidal field at both small and large scales. Satellites show a radial alignment within the one-halo term region, and low mass satellites have an intriguing alignment signal in the two-halo term region.We also forecast a feasibility to measure the intrinsic alignment power spectrum for spectroscopic and imaging surveys such as Subaru HSC/PFS and DESI.Our results thus suggest that galaxy intrinsic alignment can be used as a promising tool for constraining the galaxy formation models.

The elephant in the bathtub: when the physics of star formation regulate the baryon cycle of galaxies

ABSTRACT In simple models of galaxy formation and evolution, star formation is solely regulated by the amount of gas present in the galaxy. However, it has recently been shown that star formation can be suppressed by galactic dynamics in galaxies that contain a dominant spheroidal component and a low gas fraction. This ‘dynamical suppression’ is hypothesized to also contribute to quenching gas-rich galaxies at high redshift, but its impact on the galaxy population at large remains unclear. In this paper, we assess the importance of dynamical suppression in the context of gas regulator models of galaxy evolution through hydrodynamic simulations of isolated galaxies, with gas-to-stellar mass ratios of 0.01–0.20 and a range of galactic gravitational potentials from disc-dominated to spheroidal. Star formation is modelled using a dynamics-dependent efficiency per free-fall time, which depends on the virial parameter of the gas. We find that dynamical suppression becomes more effective at lower gas fractions and quantify its impact on the star formation rate as a function of gas fraction and stellar spheroid mass surface density. We combine the results of our simulations with observed scaling relations that describe the change of galaxy properties across cosmic time, and determine the galaxy mass and redshift range where dynamical suppression may affect the baryon cycle. We predict that the physics of star formation can limit and regulate the baryon cycle at low redshifts (z ≲ 1.4) and high galaxy masses (M* ≳ 3 × 1010 M⊙), where dynamical suppression can drive galaxies off the star formation main sequence.

Tensorial solution of the Poisson equation and the dark matter amount and distribution of UGC 8490 and UGC 9753

ABSTRACT In the first part of this article we expand three fundamental aspects of the methodology connected to the determination of a relation among the spatial density and the gravitational potential that can be specialized to distinct mass density agglomerations. As a consequence, we obtain general relations for the diagonal entries of a square symmetric matrix without zeros, we provide an expression of the gravitational potential, suitable, to represent several different mass density configurations, and we determine relations for the semi-axes of a triaxial spheroidal mass distribution, as a function of the spheroid mass density, volume density, and radius. In the second part of this paper, we employ the tools developed in the first part, to analyse the mass density content and the inner and global structure of the dark matter haloes of UGC 8490 and UGC 9753, through the fits to the dark matter rotation curves of the two galaxies, assuming a triaxial spheroidal dark matter mass configuration. We employ the Navarro Frenk and White, Burkert, DiCintio, Einasto and Stadel dark matter models, and we obtain that both a cored Burkert and cuspy DiCintio and Navarro Frenk and White inward dark matter distributions could represent equally well the observed data, furthermore we determine an oblate spheroidal dark matter mass density configuration for UGC 8490 and UGC 9753. The latter outcome is confirmed by the estimation of the gravitational torques exerted by the dark matter halo of each analysed galaxy, on the corresponding baryonic components.

Microfluidic Control of Tumor and Stromal Cell Spheroids Pairing and Merging for Three-Dimensional Metastasis Study.

Three-dimensional cell culture provides an efficient way to simulate the in vivo tumorigenic microenvironment where tumor-stroma interaction intrinsically plays a pivotal role. Conventional three-dimensional (3D) culture is inadequate to address precise coexistential heterogeneous pairing and quantitative measurement in a parallel algorithm format. Herein, we implemented a set of microwell array microfluidic devices to study the cell spheroids-based tumor-stromal metastatic process in vitro. This approach enables accurate one-to-one pairing between tumor and fibroblast spheroid for dissecting 3D tumor invasion in the manner of high-content imaging. On one single device, 240 addressable tumor-stroma pairings can be formed with convenient pipetting and centrifugation within a small area of 1 cm2. Consequential confocal imaging analysis disclosed that the tumor spheroid could envelop the fibroblast spheroid. Specific chemicals can effectively hamper or promote this 3D metastasis. Due to the addressable time-resolved measurements of the merging process of hundreds of doublets, our approach allows us to decipher the metastatic phenotype between different tumor spheroids. Compared with traditional protocols, massive heterogeneous cellular spheroids pairing and merging using this method is well-defined with microfluidic control, which leads to a favorable high-content tumor-stroma doublet metastasis analysis. This simple technique will be a useful tool for investigating heterotypic spheroid-spheroid interactions.

Why do extremely massive disc galaxies exist today?

ABSTRACT Galaxy merger histories correlate strongly with stellar mass, largely regardless of morphology. Thus, at fixed stellar mass, spheroids and discs share similar assembly histories, both in terms of the frequency of mergers and the distribution of their mass ratios. Since mergers drive disc-to-spheroid morphological transformation, and the most massive galaxies typically have the richest merger histories, it is surprising that discs exist at all at the highest stellar masses (e.g. beyond the knee of the mass function). Using Horizon-AGN, a cosmological hydroynamical simulation, we show that extremely massive (M* &amp;gt; 1011.4 M⊙) discs are created via two channels. In the primary channel (accounting for 70${\rm {per\ cent}}$ of these systems and 8${\rm {per\ cent}}$ of massive galaxies), the most recent, significant (mass ratio &amp;gt; 1:10) merger between a massive spheroid and a gas-rich satellite ‘spins up’ the spheroid by creating a new rotational stellar component, leaving a massive disc as the remnant. In the secondary channel (accounting for 30 ${\rm {per\ cent}}$ of these systems and 3 ${\rm {per\ cent}}$ of massive galaxies), a system maintains a disc throughout its lifetime, due to an anomalously quiet merger history. Not unexpectedly, the fraction of massive discs increases towards higher redshift, due to the Universe being more gas-rich. The morphological mix of galaxies at the highest stellar masses is, therefore, a strong function of the gas fraction of the Universe. Finally, these massive discs have similar black hole masses and accretion rates to massive spheroids, providing a natural explanation for why some powerful AGN are surprisingly found in disc galaxies.

P226 Caseous calcification of the mitral annulus: a silent cause of intracardiac mass

Abstract INTRODUCTION Caseous calcification of the mitral annulus (CCMA) is a very rare variant of mitral annular calcification with a central liquefaction necrosis, being an uncommon echocardiographic finding (0.5 to 1%) which may be mistaken for an intracardiac tumor, thrombus or vegetation. This chronic degenerative process can occurs at advanced ages, particularly in women, and patients with hypertension, chronic renal failure or calcium metabolism abnormalities. Since patients often remain asymptomatic, conservative treatment for this lesion is generally sufficient. CASE REPORT DESCRIPTION We report a case of an 86-year-old female with a known history of hypertension and diabetes, who was referred to our department in order to investigate the diagnosis of an intracardiac mass visualized through a routine transthoracic echocardiography. She reported effort dyspnea, but refused to have other cardiovascular symptoms. In order to study this intracardiac mass, the patient was submitted to a transthoracic echocardiogram that showed a rounded mass of 16 × 22 mm in the anterior mitral annulus, mainly in P1 scallop, not causing valve stenosis and with a mild mitral regurgitation. This prompted the need for transesophageal echocardiography which revealed a spheroid mass of heterogeneous content with calcification points, regular edges and with faint central echo-lucent area without acoustic shadowing, attached to the anterior mitral valve leaflet. No communication with any cardiac chamber could be detected. The mass did not determine any restriction to the opening of mitral valve cusps. A cardiac MRI was requested to complete the diagnostic evaluation revealing that the lesion was located at the base of the anterior leaflet. In the T1 and T2 sequences the mass was hypointense, whereas in the perfusion sequence, no contrast penetration was detected in the mass and in the late enhancement. These findings, as well as the presence of a calcified envelope in the cardiac computed tomography scan, confirmed the suspicion of caseous calcification of the mitral annulus. DISCUSSION AND CONCLUSIONS We present an unusual case of caseous calcification of the mitral annulus in which the multi-modal approach was crucial to confirme the diagnosis. Although transthoracic echocardiography can be sensitive in the diagnosis of this entity, the diagnosis may sometimes still be inconclusive. Thus, multi-modality with transesophageal echocardiography, cardiac MRI or CT can lead to a definitive diagnosis, avoiding an mistaken diagnosis with the need of a surgical approach. Since this pathology is most frequently detected in asymptomatic patients, the patients should be treated medically and monitored clinically and echocardiographically for an early recognition of possible complications. Abstract P226 Figure. Caseous calcification of mitral annulus

P887 Two sides of the same mass

Abstract Echocardiography (echo) remains the first-line imaging modality for the evaluation of cardiac masses. Three-dimensional (3D) echo, either transthoracic or transesophageal (TTE and TEE respectively), has allowed for better definition imaging, providing more information about the size, mobility, attachment and relation of these lesions with cardiac structures. Nevertheless, due to its superior tissue characterization capability, other imaging techniques, such as cardiac magnetic resonance (CMR), are very helpful in the differential diagnosis, making multimodality imaging the most attractive option for the study of intracardiac masses. We present the case of a 85 year-old male, with paroxysmal atrial fibrillation (under effective anticoagulation), type 2 diabetes mellitus, hypertension, referred for the study of an asymptomatic cardiac mass found in a routine TTE. There were no relevant findings on physical examination. The TTE showed a bilobar spheroid mass, in the right atrium, attached to the interatrial septum, with 33x23mm and regular edges. A 3D TEE was performed confirming the previous findings, but also showing extension of this mass through the fossa ovalis membrane, reaching the left atrium; this aspect raised the doubt about either protrusion or invasion of the left atrium and, respectively, a benign (like a myxoma) versus malignant behaviour (such as a sarcoma). To better characterize this lesion, a CMR was ordered, which revealed a bilobar heterogeneous mass, attached to the right side of the interatrial septum, at the fossa ovalis membrane, without signs of adjacent tissue invasion, namely unequivocal invasion of the left atrium; it presented with intermediate T1 signal, hyperintense T2 signal and heterogeneous pattern of gadolinium enhancement, features mostly in favour of a right atrial myxoma. The complimentary study found no other relevant changes, namely no findings suggestive of endocarditis (negative blood cultures), autoimmune disease or malignancy. The patient refused undergoing heart surgery and, therefore, kept follow-up with clinical and echocardiographic stability. Although histological examination remains the only tool for definitive diagnosis, multimodality imaging allows a quite comprehensive evaluation of intracardiac masses, enlightening the differential diagnosis. Here the imaging findings helped to establish a benign origin as the most likely, very important in this case of a probable right atrial myxoma, due to its peculiar protrusion to the left atrium through the fossa ovalis membrane. Abstract P887 Figure. atrial myxoma

Three new species of Eimeria Schneider 1875 in the montane grass mouse, Akodon montensis (Rodentia: Cricetidae: Sigmodontinae), and redescription of Eimeria zygodontomyis Lainson and Shaw 1990 from southeastern Brazil

We describe three new coccidian species of the genus Eimeria Schneider 1875 (Apicomplexa: Eimeriidae) and redescribe and report Eimeria zygodontomyis Lainson and Shaw, 1990 in the montane grass mouse, Akodon montensis Thomas, 1913 from the Serra dos Órgãos National Park in southeastern Brazil. Sporulated oocysts of Eimeria zygodontomyis are ellipsoidal to cylindrical with a 0.6 (0.5-0.8)μm thick very delicate bi-layered wall; length × width (n = 49) 18.3 × 12.5 (16-20 × 11-13)μm; length/width ratio of 1.4 (1.2-1.6); 1 polar granule occasionally present; micropyle, residuum both absent. Sporocysts are ellipsoidal; length × width 8.5 × 5.2 (8-11 × 5-6)μm; length/width ratio of 1.5 (1.3-1.7)μm; Stieda body is prominent; sub-Stieda body is absent; sporocyst residuum is compact. Sporulated oocysts of Eimeria montensis n. sp. are spheroidal to subspheroidal with a 1.2 (1.0-1.4)μm thick bi-layered wall; outer layer lightly pitted; length × width (n = 30) 16.3 × 12.5 (15-17 × 13-15)μm; length/width ratio of 1.3 (1.0-1.4); 1 polar granule present; micropyle, residuum both absent. Sporocysts are ellipsoidal; length × width 7.2 × 5.1 (6-8 × 4-6)μm; length/width ratio of 1.4 (1.2-1.6); Stieda body is present, sub-Stieda body is absent; sporocyst residuum consists of small, scattered granules. Sporulated oocysts of Eimeria uricanensis n. sp. are ovoidal to pyriform with a 1.4 ( 1.3-1.6)μm thick bi-layered wall; outer layer lightly pitted; length × width (n = 40) 26.6 × 18.6 (23-30 × 17-20)μm; length/width ratio of 1.4 (1.3-1.6); 1 polar granule present; micropyle, residuum both absent. Sporocysts are ellipsoidal, length × width 13.3 × 8.0 (10-16 × 7-9)μm; length/width ratio of 1.7 (1.5-1.9); Stieda body, sub-Stieda body both absent; sporocyst residuum consists of a cluster of granules, forming a spheroid mass. Sporulated oocysts of Eimeria parnasiensis n. sp. are subspheroidal to ellipsoidal with a 1.8 ( 1.3-2.4)μm thick bi-layered wall; outer layer lightly pitted; length × width (n = 54) 28.2 × 21.9 (26-32 × 19-28)μm; length/width ratio of 1.3 (1.2-1.4); 1 polar granule present; micropyle is absent; oocyst residuum is present and consists of a cluster of granules of varying thickness. Sporocysts are ovoidal, tapering towards the Stieda body; length × width 12.2 × 7.6 (10-13 × 6-9)μm; length/width ratio of 1.6 (1.4-1.9); Stieda body is present; sub-Stieda body is absent; sporocyst residuum is present and consists of an aggregate of thin granules.

Massive spheroids can form in single minor mergers

ABSTRACT Understanding how rotationally supported discs transform into dispersion-dominated spheroids is central to our comprehension of galaxy evolution. Morphological transformation is largely merger-driven. While major mergers can efficiently create spheroids, recent work has highlighted the significant role of other processes, like minor mergers, in driving morphological change. Given their rich merger histories, spheroids typically exhibit large fractions of ‘ex situ’ stellar mass, i.e. mass that is accreted, via mergers, from external objects. This is particularly true for the most massive galaxies, whose stellar masses typically cannot be attained without a large number of mergers. Here, we explore an unusual population of extremely massive (M* &gt; 1011M⊙) spheroids, in the Horizon-AGN simulation, which exhibit anomalously low ex situ mass fractions, indicating that they form without recourse to significant merging. These systems form in a single minor-merger event (with typical merger mass ratios of 0.11–0.33), with a specific orbital configuration, where the satellite orbit is virtually co-planar with the disc of the massive galaxy. The merger triggers a catastrophic change in morphology, over only a few hundred Myr, coupled with strong in situ star formation. While this channel produces a minority (∼5 per cent) of such galaxies, our study demonstrates that the formation of at least some of the most massive spheroids need not involve major mergers – or any significant merging at all – contrary to what is classically believed.

New Horizon: On the Origin of the Stellar Disk and Spheroid of Field Galaxies at z = 0.7

Abstract The origin of the disk and spheroid of galaxies has been a key open question in understanding their morphology. Using the high-resolution cosmological simulation New Horizon, we explore kinematically decomposed disk and spheroidal components of 144 field galaxies with masses greater than at z = 0.7. The origins of stellar particles are classified according to their birthplace (in situ or ex situ) and their orbits at birth. Before disk settling, stars form mainly through chaotic mergers between protogalaxies and become part of the spheroidal component. When disk settling starts, we find that more massive galaxies begin to form disk stars from earlier epochs; massive galaxies commence to develop their disks at z ∼ 1–2, while low-mass galaxies do after z ∼ 1. The formation of disks is affected by accretion as well, as mergers can trigger gas turbulence or induce misaligned gas infall that hinders galaxies from forming corotating disk stars. The importance of accreted stars is greater in more massive galaxies, especially in developing massive spheroids. A significant fraction of the spheroids come from the disk stars that are perturbed, and this becomes more important at lower redshifts. Some (∼12.5%) of our massive galaxies develop counter-rotating disks from the gas infall misaligned with the existing disk plane, which can last for more than a gigayear until they become the dominant component and flip the angular momentum of the galaxy in the opposite direction. The final disk-to-total ratio of a galaxy needs to be understood in relation to its stellar mass and accretion history. We quantify the significance of the stars with different origins and provide them as guiding values.

Assembly of spheroid-dominated galaxies in the EAGLE simulation

Context. Despite the insights gained in the last few years, our knowledge about the formation and evolution scenario for the spheroid-dominated galaxies is still incomplete. New and more powerful cosmological simulations have been developed that together with more precise observations open the possibility of more detailed study of the formation of early-type galaxies (ETGs).Aims. The aim of this work is to analyse the assembly histories of ETGs in a Λ cold dark matter cosmology, focussing on the archeological approach given by the mass-growth histories.Methods. We inspected a sample of dispersion-dominated galaxies selected from the largest volume simulation of the EAGLE project. This simulation includes a variety of physical processes such as radiative cooling, star formation (SF), metal enrichment, and stellar and active galactic nucleus (AGN) feedback. The selected sample comprised 508 spheroid-dominated galaxies classified according to their dynamical properties. Their surface brightness profile, the fundamental relations, kinematic properties, and stellar-mass growth histories are estimated and analysed. The findings are confronted with recent observations.Results. The simulated ETGs are found to globally reproduce the fundamental relations of ellipticals. All of them have an inner disc component where residual younger stellar populations (SPs) are detected. A correlation between the inner-disc fraction and the bulge-to-total ratio is reported. We find a relation between kinematics and shape that implies that dispersion-dominated galaxies with lowV/σL(whereVis the average rotational velocity andσLthe one dimensional velocity dispersion) tend to have ellipticity smaller than ∼0.5 and are dominated by old stars. On average, less massive galaxies host slightly younger stars. More massive spheroids show coeval SPs while for less massive galaxies (stellar masses lower than ∼1010 M⊙), there is a clear trend to have rejuvenated inner regions, showing an age gap between the inner and the outer regions up to ∼2 Gyr, in apparent contradiction with observational findings. We find evidences suggesting that both the existence of the disc components with SF activity in the inner region and the accretion of satellite galaxies in outer regions could contribute to the outside-in formation history in galaxies with low stellar mass. On the other hand, there are non-negligible uncertainties in the determination of the ages of old stars in observed galaxies. Stronger supernova (SN) feedback and/or the action of AGN feedback for galaxies with stellar masses lower than 1010 M⊙could contribute to prevent the SF in the inner regions.

Age, metallicity, and star formation history of spheroidal galaxies in cluster atz∼ 1.2

We present the analysis, based on spectra collected at the Large Binocular Telescope, of the stellar populations in seven spheroidal galaxies in the cluster XLSSJ0223 at $z$$\sim$1.22. The aim is to constrain the epoch of their formation and their star formation history. Using absorption line strenghts and full spectral fitting, we derive for the stellar populations of the seven spheroids a median age <Age>=2.4$\pm$0.6 Gyr, corresponding to a median formation redshift $<$$z_f$$>$$\sim2.6_{-0.5}^{+0.7}$ (lookback time = 11$_{-1.0}^{+0.6}$ Gyr). We find a significant scatter in age, showing that massive spheroids, at least in our targeted cluster, are not coeval. The median metallicity is [Z/H]=0.09$\pm$0.16, as for early-types in clusters at 0$<$$z$<0.9. This lack of evolution of [Z/H] over the range 0$<$$z$$<$1.3, corresponding to the last 9 billions years, suggests that no significant additional star formation and chemical enrichment are required for cluster spheroids to reach the present-day population. We do not detect significant correlation between age and velocity dispersion $\sigma_e$, or dynamical mass M$_{dyn}$, or effective stellar mass density $\Sigma_e$. On the contrary, the metallicity [Z/H] of the seven spheroids is correlated to their dynamical mass M$_{dyn}$, according to a relation similar to the one for local spheroids. [Z/H] is also anticorrelated to stellar mass density $\Sigma_e$ because of the anticorrelation between M$_{dyn}$ and $\Sigma_e$. Therefore, the basic trends observed in the local universe were already established at $z\sim1.3$, i.e. more massive spheroids are more metal rich, have lower stellar mass density and tend to be older than lower-mass galaxies.

Hot Atmospheres, Cold Gas, AGN Feedback and the Evolution of Early Type Galaxies: A Topical Perspective

Most galaxies comparable to or larger than the mass of the Milky Way host hot, X-ray emitting atmospheres, and many such galaxies are radio sources. Hot atmospheres and radio jets and lobes are the ingredients of radio-mechanical active galactic nucleus (AGN) feedback. While a consensus has emerged that such feedback suppresses cooling of hot cluster atmospheres, less attention has been paid to massive galaxies where similar mechanisms are at play. Observation indicates that the atmospheres of elliptical and S0 galaxies were accreted externally during the process of galaxy assembly and augmented significantly by stellar mass loss. Their atmospheres have entropy and cooling time profiles that are remarkably similar to those of central cluster galaxies. About half display filamentary or disky nebulae of cool and cold gas, much of which has likely cooled from the hot atmospheres. We review the observational and theoretical perspectives on thermal instabilities in galactic atmospheres and the evidence that AGN heating is able to roughly balance the atmospheric cooling. Such heating and cooling may be regulating star formation in all massive spheroids at late times.

The host galaxies of luminous type 2 AGNs atz∼ 0.3–0.4

We study the morphological and structural properties of the host galaxies associated with 57 optically-selected luminous type 2 AGN at $z\sim$0.3-0.4: 16 high-luminosity Seyfert 2 (HLSy2, 8.0$\le$log($L_{\rm [OIII]}/L_{\odot})<$8.3) and 41 obscured quasars (QSO2, log($L_{\rm [OIII]}/L_{\odot})\ge$8.3). With this work, the total number of QSO2 at $z<1$ with parametrized galaxies increases from $\sim$35 to 76. Our analysis is based on HST WFPC2 and ACS images that we fit with {\sc GALFIT}. HLSy2 and QSO2 show a wide diversity of galaxy hosts. The main difference lies in the higher incidence of highly-disturbed systems among QSO2. This is consistent with a scenario in which galaxy interactions are the dominant mechanism triggering nuclear activity at the highest AGN power. There is a strong dependence of galaxy properties with AGN power (assuming $L_ {\rm [OIII]}$ is an adequate proxy). The relative contribution of the spheroidal component to the total galaxy light (B/T) increases with $L_ {\rm [OIII]}$. While systems dominated by the spheoridal component spread across the total range of $L_ {\rm [OIII]}$, most disk-dominated galaxies concentrate at log($L_{\rm [OIII]}/L_{\odot})<$8.6. This is expected if more powerful AGN are powered by more massive black holes which are hosted by more massive bulges or spheroids. The average galaxy sizes ($\langle r_{\rm e} \rangle$) are 5.0$\pm$1.5 kpc for HLSy2 and 3.9$\pm$0.6 kpc for HLSy2 and QSO2 respectively. These are significantly smaller than those found for QSO1 and narrow line radio galaxies at similar $z$. We put the results of our work in context of related studies of AGN with quasar-like luminosities.