Large-scale Kinematics Research Articles

Spatially resolved spectroscopic analysis of Lyα haloes

The extended Lyα haloes (LAHs) have been found to be prevalent around high-redshift star-forming galaxies. However, the origin of the LAHs is still a subject of debate. The spatially resolved analysis of Lyα profiles provides an important diagnostic. We analyse the average spatial extent and spectral variation of the circumgalactic LAHs by stacking a sample of 155 Lyα emitters (LAEs) at redshifts of 3 < z < 4 in the MUSE Extremely Deep Field. Our analysis reveals that, with respect to the Lyα line of the target LAE, the peak of the Lyα line at large distances becomes increasingly more blueshifted up to a projected distance of 60 kpc (≈3× virial radius), with a velocity offset of ≈250 km/s. This trend is evident in both the mean and median stacks, suggesting that it is a general property of our LAE sample, which typically has a Lyα luminosity of ≈1041.1 erg s−1. However, due to the absence of systemic redshift data, it remains unclear whether the Lyα line peak at large projected distances is less redshifted compared to the inner regions or truly blueshifted with respect to the systemic velocity. We explore various scenarios to explain the large-scale kinematics of the Lyα line.

Structural evolution, segmentation and activity of the onshore-offshore Waimea-Flaxmore Fault System in south-eastern Tasman Bay, South Island, New Zealand

ABSTRACT The Waimea-Flaxmore Fault System (W-FFS) from the Nelson-Richmond urban area to D’Urville Island is analysed through six regional transects that join depth-converted seismic lines in Tasman Bay to onshore cross sections. Reverse reactivation of basement faults of the W-FFS by mechanisms of fault-propagation folding at c. 19-10 Ma occurred along the entire length of the fault system. However, the W-FFS remained Quaternary active only from the vicinity of Cape Soucis southwards into onshore Nelson, in contrast with cessation of activity along eastern Tasman Bay since 7 Ma. The inactive western faults of the W-FFS are buried below Plio-Quaternary marine sediments and segmented by the newly identified, c. E-W, Croisilles Fault Zone, Cross Point and D’Urville faults, with cumulative dextral offset of c. 27 km. The c. E-W faults extend from the onshore into Tasman Bay and are interpreted as the northernmost Late Miocene strands of the Marlborough Fault System that have accommodated incipient distributed shear in the crustal block north of the Queen Charlotte Fault Zone. Segmentation and along-strike changes of the W-FFS occur at the transition from the contractional domain of onshore Nelson to the northern Marlborough strike-slip domain, driven by large-scale kinematics of the Australia-Pacific plate boundary.

The Mass of the Black Hole in NGC 5273 from Stellar Dynamical Modeling

We present a new constraint on the mass of the black hole in the active S0 galaxy NGC 5273. Due to the proximity of the galaxy at 16.6 ± 2.1 Mpc, we were able to resolve and extract the bulk motions of stars near the central black hole using adaptive-optics-assisted observations with the Gemini Near-infrared Integral Field Spectrograph, as well as constrain the large-scale kinematics using archival Spectroscopic Areal Unit for Research and Optical Nebulae spectroscopy. High-resolution Hubble Space Telescope imaging allowed us to generate a surface-brightness decomposition, determine approximate mass-to-light ratios for the bulge and disk, and obtain an estimate for the disk inclination. We constructed an extensive library of dynamical models using the Schwarzschild orbit-superposition code FORSTAND, exploring a range of disk and bulge shapes, halo masses, etc. We determined a black hole mass of M • = [0.5–2] × 107 M ⊙, where the low side of the range is in agreement with the reverberation mapping measurement of M • = [4.7 ± 1.6] × 106 M ⊙. NGC 5273 is one of the few nearby galaxies that hosts a broad-lined active galactic nucleus, allowing a crucial comparison of black hole masses derived from independent mass-measurement techniques.

On the 3D Curvature and Dynamics of the Musca Filament

Filaments are ubiquitous in the interstellar medium, yet their formation and evolution remain the topic of intense debate. In order to obtain a more comprehensive view of the 3D morphology and evolution of the Musca filament, we model the C18O(2-1) emission along the filament crest with several large-scale velocity field structures. This indicates that Musca is well described by a 3D curved cylindrical filament with longitudinal mass inflow to its center unless the filament is a transient structure with a lifetime ≲0.1 Myr. Gravitational longitudinal collapse models of filaments appear unable to explain the observed velocity field. To better understand these kinematics, we further analyze a map of the C18O(2-1) velocity field at the location of SOFIA HAWC+ dust polarization observations that trace the magnetic field in the filament. This unveils an organized magnetic field that is oriented roughly perpendicular to the filament crest. Although the velocity field is also organized, it progressively changes its orientation by more than 90° when laterally crossing the filament crest and thus appears disconnected from the magnetic field in the filament. This strong lateral change of the velocity field over the filament remains unexplained and might be associated with important longitudinal motion that can be associated to the large-scale kinematics along the filament.

A Large (≈ 1 pc) Contracting Envelope Around the Prestellar Core L1544* *This work is based on observations carried out with the IRAM 30m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).

Prestellar cores, the birthplace of Sun-like stars, form from the fragmentation of the filamentary structure that composes molecular clouds, from which they must inherit at least partially the kinematics. Furthermore, when they are on the verge of gravitational collapse, they show signs of subsonic infall motions. How extended these motions are, which depends on how the collapse occurs, remains largely unknown. We want to investigate the kinematics of the envelope that surrounds the prototypical prestellar core L1544, studying the cloud-core connection. To our aims, we observed the HCO+ (1–0) transition in a large map. HCO+ is expected to be abundant in the envelope, making it an ideal probe of the large-scale kinematics in the source. We modeled the spectrum at the dust peak by means of a nonlocal thermodynamical equilibrium radiative transfer. In order to reproduce the spectrum at the dust peak, a large (∼1 pc) envelope is needed, with low density (tens of cm−3 at most) and contraction motions, with an inward velocity of ≈ 0.05 km s−1. We fitted the data cube using the Hill5 model, which implements a simple model for the optical depth and excitation temperature profiles along the line of sight, in order to obtain a map of the infall velocity. This shows that the infall motions are extended, with typical values in the range 0.1–0.2 km s−1. Our results suggest that the contraction motions extend in the diffuse envelope surrounding the core, which is consistent with recent magnetic field measurements in the source, which showed that the envelope is magnetically supercritical.

Synthetic Next Generation Very Large Array line observations of a massive star-forming cloud

Context. Studies of the interstellar medium and the pre-stellar cloud evolution require spectral line observations that have a high sensitivity and high angular and velocity resolution. Regions of high-mass star formation are particularly challenging because of line-of-sight confusion, inhomogeneous physical conditions, and potentially very high optical depths. Aims. We wish to quantify to what accuracy the physical conditions within a massive star-forming cloud can be determined from observations. We are particularly interested in the possibilities offered by the Next Generation Very Large Array (ngVLA) interferometer. Methods. We used data from a magnetohydrodynamic simulation of star formation in a high-density environment. We concentrated on the study of a filamentary structure that has physical properties similar to a small infrared-dark cloud. We produced synthetic observations for spectral lines observable with the ngVLA and analysed these to measure column density, gas temperature, and kinematics. Results were compared to ideal line observations and the actual 3D model. Results. For a nominal cloud distance of 4kpc, ngVLA provides a resolution of ~0.01 pc even in its most compact configuration. For abundant molecules, such as HCO+, NH3, N2H+, and CO isotopomers, cloud kinematics and structure can be mapped down to subarcsecond scales in just a few hours. For NH3, a reliable column density map could be obtained for the entire 15″ × 40″ cloud, even without the help of additional single-dish data, and kinetic temperatures are recovered to a precision of ~1 K. At higher frequencies, the loss of large-scale emission becomes noticeable. The line observations are seen to accurately trace the cloud kinematics, except for the largest scales, where some artefacts appear due to the filtering of low spatial frequencies. The line-of-sight confusion complicates the interpretation of the kinematics, and the usefulness of collapse indicators based on the expected blue asymmetry of optically thick lines is limited. Conclusions. The ngVLA will be able to provide accurate data on the small-scale structure and the physical and chemical state of star-forming clouds, even in high-mass star-forming regions at kiloparsec distances. Complementary single-dish data are still essential for estimates of the total column density and the large-scale kinematics.

Large-scale expansion of OB stars in Cygnus

ABSTRACT The proper motions (PMs) of OB stars in Cygnus have recently been found to exhibit two large-scale kinematic patterns suggestive of expansion. We perform a 3D traceback on these OB stars, the newly identified OB associations and related open clusters in the region. We find that there are two groups of stars, associations and clusters and that they were each more compact in the past, reaching their closest approach $7.9^{+3.0}_{-1.8}$ and $8.5^{+0.8}_{-2.8}$ Myr ago. We consider two main scenarios for the driver of these large-scale expansion patterns: feedback-driven expansion from a previous generation of massive stars, and expansion as a result of the turbulent velocity field in the primordial molecular cloud. While it is tempting to attribute such large-scale expansion patterns to feedback processes, we find that the observed kinematics are fully consistent with the turbulent origin, and therefore that the injection of further energy or momentum from feedback is not required. Similar conclusions may be drawn for other star forming regions with large-scale expansion patterns.

Kinematic footprint of the Milky Way spiral arms in Gaia EDR3

ABSTRACT The Milky Way spiral arms are well established from star counts as well as from the locus of molecular clouds and other young objects; however, they have only recently started to be observed from a kinematics point of view. Using the kinematics of thin disc stars in Gaia EDR3 around the extended solar neighbourhood, we create x–y projections coloured by the radial, residual rotational, and vertical Galactocentric velocities (U, ΔV, W). The maps are rich in substructures and reveal the perturbed state of the Galactic disc. We find that local differences between rotational velocity and the azimuthally averaged velocity, ΔV, display at least five large-scale kinematic spirals; two of them closely follow the locus of the Sagittarius-Carina and Perseus spiral arms, with pitch angles of 9.12° and 7.76°, and vertical thickness of ∼400 pc and ∼600 pc, respectively. Another kinematic spiral is located behind the Perseus arm and appears as a distortion in rotation velocities left by this massive arm but with no known counterpart in gas or stars overdensity. A weaker signal close to the Sun’s position is present in our three velocity maps, and appears to be associated with the Local arm. Our analysis of the stellar velocities in the Galactic disc shows kinematic differences between arms and interarms that are in favour of Milky Way spiral arms that do not corotate with the disc. Moreover, we show that the kinematic spirals are clumpy and flocculent, revealing the underlying nature of the Milky Way spiral arms.

Microstructure and Crystallographic Preferred Orientations of an Azimuthally Oriented Ice Core from a Lateral Shear Margin: Priestley Glacier, Antarctica

A 58 m long azimuthally oriented ice core has been collected from the floating lateral sinistral shear margin of the lower Priestley Glacier, Terra Nova Bay, Antarctica. The crystallographic preferred orientations (CPO) and microstructures are described in order to correlate the geometry of anisotropy with constrained large-scale kinematics. Cryogenic Electron Backscatter Diffraction analysis shows a very strong fabric (c-axis primary eigenvalue ∼0.9) with c-axes aligned horizontally sub-perpendicular to flow, rotating nearly 40° clockwise (looking down) to the pole to shear throughout the core. The c-axis maximum is sub-perpendicular to vertical layers, with the pole to layering always clockwise of the c-axes. Priestley ice microstructures are defined by largely sub-polygonal grains and constant mean grain sizes with depth. Grain long axis shape preferred orientations (SPO) are almost always 1–20° clockwise of the c-axis maximum. A minor proportion of “oddly” oriented grains that are distinct from the main c-axis maximum, are present in some samples. These have horizontal c-axes rotated clockwise from the primary c-axis maximum and may define a weaker secondary maximum up to 30° clockwise of the primary maximum. Intragranular misorientations are measured along the core, and although the statistics are weak, this could suggest recrystallization by subgrain rotation to occur. These microstructures suggest subgrain rotation (SGR) and recrystallization by grain boundary migration recrystallization (GBM) are active in the Priestley Glacier shear margin. Vorticity analysis based on intragranular distortion indicates a vertical axis of rotation in the shear margin. The variability in c-axis maximum orientation with depth indicates the structural heterogeneity of the Priestley Glacier shear margin occurs at the meter to tens of meters scale. We suggest that CPO rotations could relate to rigid rotation of blocks of ice within the glacial shear margin. Rotation either post-dates CPO and SPO development or is occurring faster than CPO evolution can respond to a change in kinematics.

Formation of the Musca filament: evidence for asymmetries in the accretion flow due to a cloud–cloud collision

Context.Dense molecular filaments are ubiquituous in the interstellar medium, yet their internal physical conditions and the role of gravity, turbulence, the magnetic field, radiation, and the ambient cloud during their evolution remain debated.Aims.We study the kinematics and physical conditions in the Musca filament, the ambient cloud, and the Chamaeleon-Musca complex to constrain the physics of filament formation.Methods.We produced CO(2–1) isotopologue maps with the APEX telescope that cut through the Musca filament. We further study a NANTEN212CO(1–0) map of the full Musca cloud, H Iemission of the Chamaeleon-Musca complex, aPlanckpolarisation map, line radiative transfer models,Gaiadata, and synthetic observations from filament formation simulations.Results.The Musca cloud, with a size of ~3–6 pc, contains multiple velocity components. Radiative transfer modelling of the CO emission indicates that the Musca filament consists of a cold (~10 K), dense (nH2∼ 104cm−3) crest, which is best described with a cylindrical geometry. Connected to the crest, a separate gas component atT~ 15 K andnH2∼ 103cm−3is found, the so-called strands. The velocity-coherent filament crest has an organised transverse velocity gradient that is linked to the kinematics of the nearby ambient cloud. This velocity gradient has an angle ≥30° with respect to the local magnetic field orientation derived fromPlanck, and the magnitude of the velocity gradient is similar to the transonic linewidth of the filament crest. Studying the large scale kinematics, we find coherence of the asymmetric kinematics from the 50 pc H Icloud down to the Musca filament. We also report a strong [C18O]/[13CO] abundance drop by an order of magnitude from the filament crest to the strands over a distance <0.2 pc in a weak ambient far-ultraviolet (FUV) field.Conclusions.The dense Musca filament crest is a long-lived (several crossing times), dynamic structure that can form stars in the near future because of continuous mass accretion replenishing the filament. This mass accretion on the filament appears to be triggered by a H Icloud–cloud collision, which bends the magnetic field around dense filaments. This bending of the magnetic field is then responsible for the observed asymmetric accretion scenario of the Musca filament, which is, for instance, seen as a V-shape in the position–velocity (PV) diagram.

Quantifying the Stellar Halo's Response to the LMC's Infall with Spherical Harmonics

Abstract The vast majority of the mass in the Milky Way (MW) is in dark matter (DM); we therefore cannot directly observe the MW mass distribution and have to use tracer populations in order to infer properties of the MW DM halo. However, MW halo tracers do not only feel the gravitational influence of the MW itself. Tracers can also be affected by MW satellites; Garavito-Camargo et al. (2109) demonstrate that the Large Magellanic Cloud (LMC) induces a density wake in the MW DM, resulting in large-scale kinematic patterns in the MW stellar halo. In this work, we use spherical harmonic expansion (SHE) of the velocity fields of simulated stellar halos in an effort to disentangle perturbations on large scales (e.g., due to the LMC itself, as well as the LMC-induced DM wake) and small scales (due to substructure). Using the Garavito-Camargo et al. simulations, we demonstrate how the different terms in the SHE of the stellar velocity field reflect the different wake components and show that these signatures are a strong function of the LMC mass. An exploration of model halos built from accreted dwarfs suggests that stellar debris from massive, recent accretion events can produce much more power in the velocity angular power spectra than the perturbation from the LMC-induced wake. We therefore consider two models for the Sagittarius (Sgr) stream—the most recent, massive accretion event in the MW apart from the LMC—and find that the angular power on large scales is generally dominated by the LMC-induced wake, even when Sgr is included. We conclude that SHE of the MW stellar halo velocity field may therefore be a useful tool in quantifying the response of the MW DM halo to the LMC’s infall.

Seismotectonics and 1-D velocity model of the Greater Geneva Basin, France–Switzerland

SUMMARY The Greater Geneva Basin (GGB), located in southwestern Switzerland and neighboring France, is enclosed by the rotating northwestern edge of the Alpine front and the Jura mountains chain. Recently, this basin has received increasing attention as a target for geothermal exploration. Historical and instrumental seismicity suggest that faults affecting the basin may still be active. Moderate-magnitude earthquakes have been located along the Vuache fault, a major strike-slip structure crossing the basin. Before geothermal exploration starts, it is key to evaluate the seismic rate in the region and identify possible seismogenic areas. In this context, we deployed a temporary seismic network of 20 broad-band stations (from September 2016 to January 2018) to investigate the ongoing seismic activity, its relationship with local tectonic structures, and the large-scale kinematics of the area. Our network lowered the magnitude of completeness of the permanent Swiss and French networks from 2.0 to a theoretical value of 0.5. Using a new coherence-based detector (LASSIE - particularly effective to detect microseismicity in noisy environments), we recorded scarce seismicity in the basin with local magnitudes ranging from 0.7 to 2.1 ML. No earthquakes were found in the Canton of Geneva where geothermal activities will take place. We constructed a local ’minimum 1-D P-wave velocity model’ adapted to the GGB using earthquakes from surrounding regions. We relocated the events of our catalogue obtaining deeper hypocentres compared to the locations obtained using the available regional velocity models. We also retrieved eight new focal mechanisms using a combination of polarities and waveform inversion techniques (CSPS). The stress inversion shows a pure strike-slip stress regime, which is in agreement with structural and geological data. Combining the background seismicity with our catalogue, we identified seismogenic areas offsetting the basin.

AGN-Driven Outflows in Dwarf Galaxies

Abstract We present spatially resolved kinematic measurements of active galactic nucleus (AGN)-driven outflows in dwarf galaxies in the stellar mass range ∼6 × 108–9 × 109 M ⊙, selected from SDSS DR7 and DR8 and followed-up with Keck/LRIS spectroscopy. We find spatially extended (∼1 half-light radius), high-velocity ionized gas outflows (W 80 up to ∼2000 km s−1) in 13/50 dwarf galaxies with and without an AGN. Outflow velocities in all 13 galaxies exceed the escape velocities of their halos. Nine of these 13 galaxies are classified as AGNs according to their narrow line flux ratios. Of these, six have outflow components with emission-line ratios consistent with AGN ionization. Although black holes (BHs) have been known to populate the centers of at least a few dwarf galaxies and indirect evidence of AGN quenching of star formation in dwarfs has begun to surface, our measurements constitute the first direct detection and measurement of AGN impact on the large-scale kinematics and gas content in dwarf galaxies. Furthermore, we find evidence suggestive of ongoing star formation suppression, possibly regulated by the AGN. Galaxy formation models must therefore be able to account not only for the formation and growth of BHs at the centers of dwarf galaxies, but should also be revised to include AGNs as important—and perhaps dominant—sources of feedback in low-mass galaxies.

Sea cliff at Wissower Bach (Pleistocene stripe 5) – microstructural evidence of large-scale glacitectonism and glacier kinematics

Abstract. Soft-sediment thin sections from a SW-dipping thrust fault at the south-western limb of the Wissower Bach syncline (NE Rügen) give rise to the complicated glacitectonic environment in the south-western Baltic Sea region. Micromorphology, microstructural mapping, and macroscale information have led to the development of a detailed model for the evolution of the syncline during late Weichselian glacitectonism.

The Galactic warp revealed by Gaia DR2 kinematics

ABSTRACT Using Gaia DR2 astrometry, we map the kinematic signature of the Galactic stellar warp out to a distance of 7 kpc from the Sun. Combining Gaia DR2 and 2-Micron All Sky Survey photometry, we identify, via a probabilistic approach, $599 \, 494$ upper main sequence (UMS) stars and $12\, 616\, 068$ giants without the need for individual extinction estimates. The spatial distribution of the UMS stars clearly shows segments of the nearest spiral arms. The large-scale kinematics of both the UMS and giant populations show a clear signature of the warp of the Milky Way, apparent as a gradient of 5–6 km s−1 in the vertical velocities from 8 to 14 kpc in Galactic radius. The presence of the signal in both samples, which have different typical ages, suggests that the warp is a gravitationally induced phenomenon.

A quartet of black holes and a missing duo: probing the low end of the MBH–σ relation with the adaptive optics assisted integral-field spectroscopy

We present mass estimates of supermassive black holes in six nearby fast rotating early-type galaxies (NGC4339, NGC4434, NGC4474, NGC4551, NGC4578 and NGC4762) with effective stellar velocity dispersion around 100 km/s. We use near-infrared laser-guide adaptive optics observations with the GEMINI/NIFS to derive stellar kinematics in the galactic nuclei, and SAURON observations from the ATLAS3D Survey for large-scale kinematics. We build axisymmetric Jeans anisotropic models and axisymmetric Schwarzschild dynamical models. Both modelling approaches recover consistent orbital anisotropies and black hole masses within 1-2sigma confidence level, except for one galaxy for which the difference is just above the 3sigma level. Two black holes (NGC4339 and NGC4434) are amongst the largest outliers from the current black hole mass - velocity dispersion relation, with masses of $(4.3^{+4.8}_{-2.3})\times10^7$ and $(7.0^{+2.0}_{-2.8})\times10^7$ M$_\odot$, respectively ($3\sigma$ confidence level). The black holes in NGC4578 and NGC4762 lie on the scaling relation with masses of $(1.9^{+0.6}_{-1.4})\times10^7$ and $(2.3^{+0.9}_{-0.6})\times10^7$ M$_\odot$, respectively (3sigma confidence level). For two galaxies (NGC4474 and NGC4551) we are able to place upper limits on their black holes masses ($<7\times10^6$ and $<5\times10^6$ M$_\odot$, respectively, $3\sigma$ confidence level). The kinematics for these galaxies clearly indicate central velocity dispersion drops within a radius of 35 pc and 80 pc, respectively. These drops cannot be associated with cold stellar structures and our data do not have the resolution to exclude black holes with masses an order of magnitude smaller than the predictions. Parametrizing the orbital distribution in spherical coordinates, the vicinity of the black holes is characterized by isotropic or mildly tangential anisotropy.

An HST/COS legacy survey of high-velocity ultraviolet absorption in the Milky Way’s circumgalactic medium and the Local Group

To characterize the absorption properties of this circumgalactic medium (CGM) and its relation to the LG we present the so-far largest survey of metal absorption in Galactic high-velocity clouds (HVCs) using archival ultraviolet (UV) spectra of extragalactic background sources. The UV data are obtained with the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope (HST) and are supplemented by 21 cm radio observations of neutral hydrogen. Along 270 sightlines we measure metal absorption in the lines of SiII, SiIII, CII, and CIV and associated HI 21 cm emission in HVCs in the velocity range |v_LSR|=100-500 km s^-1. With this unprecedented large HVC sample we were able to improve the statistics on HVC covering fractions, ionization conditions, small-scale structure, CGM mass, and inflow rate. For the first time, we determine robustly the angular two point correlation function of the high-velocity absorbers, systematically analyze antipodal sightlines on the celestial sphere, and compare the absorption characteristics with that of Damped Lyman alpha absorbers (DLAs) and constrained cosmological simulations of the LG. Our study demonstrates that the Milky Way CGM contains sufficient gaseous material to maintain the Galactic star-formation rate at its current level. We show that the CGM is composed of discrete gaseous structures that exhibit a large-scale kinematics together with small-scale variations in physical conditions. The Magellanic Stream clearly dominates both the cross section and mass flow of high-velocity gas in the Milky Way's CGM. The possible presence of high-velocity LG gas underlines the important role of the local cosmological environment in the large-scale gas-circulation processes in and around the Milky Way (abridged).

Temperature structure and kinematics of the IRDC G035.39–00.33

Aims. Infrared dark clouds represent the earliest stages of high-mass star formation. Detailed observations of their physical conditions on all physical scales are required to improve our understanding of their role in fueling star formation. Methods. We investigate the large-scale structure of the IRDC G035.39-00.33, probing the dense gas with the classical ammonia thermometer. This allows us to put reliable constraints on the temperature of the extended, pc-scale dense gas reservoir and to probe the magnitude of its non-thermal motions. Available far-infrared observations can be used in tandem with the observed ammonia emission to estimate the total gas mass contained in G035.39-00.33. Results. We identify a main velocity component as a prominent filament, manifested as an ammonia emission intensity ridge spanning more than 6 pc, consistent with the previous studies on the Northern part of the cloud. A number of additional line-of-sight components are found, and a large scale, linear velocity gradient of ~0.2 km s$^{-1}$ pc$^{-1}$ is found along the ridge of the IRDC. In contrast to the dust temperature map, an ammonia-derived kinetic temperature map, presented for the entirety of the cloud, reveals local temperature enhancements towards the massive protostellar cores. We show that without properly accounting for the line of sight contamination, the dust temperature is 2-3 K larger than the gas temperature measured with NH$_3$. Conclusions. While both the large scale kinematics and temperature structure are consistent with that of starless dark filaments, the kinetic gas temperature profile on smaller scales is suggestive of tracing the heating mechanism coincident with the locations of massive protostellar cores.

FOREST unbiased Galactic plane imaging survey with the Nobeyama 45 m telescope (FUGIN). I. Project overview and initial results

Abstract The FUGIN project is one of legacy projects using a new multi-beam FOREST (four-beam receiver system on the 45 m telescope). This project aims to simultaneously investigate the distribution, kinematics, and physical properties of both diffuse and dense molecular gases in the Galaxy by observing 12CO, 13CO, and C18O J = 1–0 lines simultaneously. Mapping regions are parts of the first quadrant (10° ≤ l ≤ 50°, |b| ≤ 1°) and the third quadrant (198° ≤ l ≤ 236°, |b| ≤ 1°) of the Galaxy, where spiral arms, bar structure, and the molecular gas ring are included. This survey achieves the highest angular resolution to date (∼20″) for the Galactic plane survey in the CO J = 1–0 lines, which makes it possible to find dense clumps located farther away than the previous surveys. FUGIN will provide us an invaluable dataset for investigating the physics of the Galactic interstellar medium (ISM), particularly the evolution of interstellar gas covering galactic-scale structures to the internal structures of giant molecular clouds, such as small filaments/clumps/cores. We present an overview of the FUGIN project, the observation plan and initial results. These results reveal wide-field and detailed structures of molecular clouds, such as entangled filaments that have not been obvious in previous surveys, and large-scale kinematics of molecular gas, such as spiral arms.

A Black Hole Mass Determination for the Compact Galaxy Mrk 1216

Abstract Mrk 1216 is a nearby, early-type galaxy with a small effective radius of 2.8 kpc and a large stellar velocity dispersion of 308 km s−1 for its K-band luminosity of . Using integral field spectroscopy assisted by adaptive optics from Gemini North, we measure spatially resolved stellar kinematics within ∼450 pc of the galaxy nucleus. The galaxy exhibits regular rotation with velocities of ±180 km s−1 and a sharply peaked velocity dispersion profile that reaches 425 km s−1 at the center. We fit axisymmetric, orbit-based dynamical models to the combination of these high angular resolution kinematics, large-scale kinematics extending to roughly three effective radii, and Hubble Space Telescope imaging, resulting in a constraint of the mass of the central black hole in Mrk 1216. After exploring several possible sources of systematics that commonly affect stellar-dynamical black hole mass measurements, we find a black hole mass of and an H-band stellar mass-to-light ratio of (1σ uncertainties). Mrk 1216 is consistent with the local black hole mass–stellar velocity dispersion relation, but is a factor of ∼5–10 larger than expectations from the black hole mass–bulge luminosity and black hole mass–bulge mass correlations when conservatively using the galaxy’s total luminosity or stellar mass. This behavior is quite similar to the extensively studied compact galaxy NGC 1277. Resembling the quiescent galaxies, Mrk 1216 may be a passively evolved descendant, and perhaps reflects a previous era when galaxies contained over-massive black holes relative to their bulge luminosities/masses, and the growth of host galaxies had yet to catch up.