Total Redshift Research Articles

The Heavier the Faster: A Subpopulation of Heavy, Rapidly Spinning and Quickly Evolving Binary Black Holes

Abstract The spins of binary black holes (BBHs) measured from gravitational waves contain valuable information about their formation pathways. In this study, we propose a new quantity, the “dimensionless net spin” (χ N), which relates to the sum of the angular momenta of the component black holes (BHs) in the system, offering a novel perspective for exploring the origins of BBHs. Through hierarchical Bayesian inference on χ N, we find strong evidence that its distribution is better described by two Gaussian components rather than one, and their branching ratios vary with total mass and redshift: there is a narrow peak at χ N ∼ 0.15 and an extended peak at χ N ∼ 0.3–0.6. The rapidly spinning systems likely dominate the high-mass end of the population and evolve with redshift more quickly. These findings present new challenges to the field binary formation scenario and suggest that dynamical processes may play a key role in the formation of high total mass BBHs.

The PAU survey: close galaxy pairs identification and analysis

ABSTRACT Galaxy pairs constitute the initial building blocks of galaxy evolution, which is driven through merger events and interactions. Thus, the analysis of these systems can be valuable in understanding galaxy evolution and studying structure formation. In this work, we present a new publicly available catalogue of close galaxy pairs identified using photometric redshifts provided by the Physics of the Accelerating Universe Survey (PAUS). To efficiently detect them, we take advantage of the high-precision photo−z (σ68 < 0.02) and apply an identification algorithm previously tested using simulated data. This algorithm considers the projected distance between the galaxies (rp < 50 kpc), the projected velocity difference (ΔV < 3500 km s−1) and an isolation criterion to obtain the pair sample. We applied this technique to the total sample of galaxies provided by PAUS and to a subset with high-quality redshift estimates. Finally, the most relevant result we achieved was determining the mean mass for several subsets of galaxy pairs selected according to their total luminosity, colour, and redshift, using galaxy–galaxy lensing estimates. For pairs selected from the total sample of PAUS with a mean r-band luminosity 1010.6 h−2 L⊙, we obtain a mean mass of M200 = 1012.2 h−1 M⊙, compatible with the mass–luminosity ratio derived for elliptical galaxies. We also study the mass-to-light ratio M/L as a function of the luminosity L and find a lower M/L (or steeper slope with L) for pairs than the one extrapolated from the measurements in groups and galaxy clusters.

Bandgap engineering of CdTe/CdSe rod-shaped core/shell and CdTeSe ellipsoidal alloy quantum dots with tunable and intense emission

In this work, core CdTe, core-shell CdTe/CdSe and alloy CdTeSe QDs are synthesized by aqueous solvent. TEM visually shows the rod-shaped core-shell structure with a transverse to longitudinal ratio of 6.5 and the ellipsoidal alloy structure with different crystal planes competing for growth. The XRD and Raman spectra of the three QDs illustrate the characteristics of the internal lattice structure. With the increase of reaction time, CdTe emission maximum (EM) shows a red shift of 84 nm. Stokes shift changes little, and full width half maximum (FWHM) increases slightly. Compared with the CdTe, the red shift of CdTe/CdSe EM is slowly first and then faster, with a total shift of 125 nm. Stokes shift increases obviously. The initial FWHM is larger than CdTe and the widening speed is gradually accelerated. The initial EM of CdTeSe is red shifted compared with CdTe, and the total red shift of EM is 72 nm. Stokes shift increases obviously. The initial FWHM is significantly wider than CdTe. FWHM first decreases and then increases with reaction time. CdTe shows obvious band edge exciton absorbance of photoluminescence excitation (PLE) spectrum between 356 nm and 400 nm. CdTe/CdSe shows double band edge exciton absorption at 354–373 nm and 401–436 nm due to wave function separated of core-shell structure. The PLE spectrum of CdTeSe shows an obvious upward trend at 306–373 nm due to high energy level nonradiation. The average lifetime of CdTe/CdSe increases by 53 ns compared with CdTe due to the spatially separated electrons and holes. The defect state of CdTeSe increases the proportion of fast delay, which is 2 ns shorter than the average lifetime of CdTe. The transition mechanism of core-shell indirect band gap and alloy direct band gap is explained according to the valence bands of each element shown by XPS and the simulation of energy band density of states. The thickness shell and the doping elements can be adjusted to provide rich variation in the optical properties. This provides a more definite direction for the applications of cadmium chalcogenide in the fields of photoelectric devices and biology. • Type I and type II transformation through Rod-shaped core/shell and ellipsoidal alloy QDs. • Tunable emission achieved by adjusting morphology, lattice structure and valence bond connection. • Precise and rich regulation of band gap engineering. • Providing a more definite direction for the applications of cadmium chalcogenide QDs.

Temperature tunable electromagnetically induced transparency in terahertz metasurface fabricated on ferroelectric platform

The integration of active materials in terahertz (THz) metasurfaces is pivotal for the realization of functional device applications in diverse fields like sensing, imaging, communication, etc. In this context, ferroelectric materials endowed with tunable electro-optic properties have recently emerged as a novel candidate for achieving actively tuned THz metasurfaces. Here, we experimentally investigate temperature tuning of electromagnetically induced transparency (EIT) effects in a THz metasurface based on ferroelectric barium titanate (BaTiO3 (BTO)) thin film. We characterize tunable dielectric properties of the BTO thin film under variable temperatures (25 °C–100 °C) at THz frequencies by utilizing THz-time domain spectroscopy technique. Based on this aspect, we design a THz metasurface capable of displaying the EIT effect. THz transmissions through the metasurface sample are then probed for different applied temperatures. The EIT features undergo frequency shifts along with amplitude modulations owing to the temperature induced variations of the dielectric properties of the BTO thin film. A total red shift ∼27 GHz in EIT resonance dip is observed experimentally as the temperature increases from 25 °C to 100 °C. Therefore, we demonstrate utilities of ferroelectric platform toward the development of temperature tunable EIT metasurfaces.

Mass and spin of Kerr black holes in terms of observational quantities: The dragging effect on the redshift

In this work, we elaborate on the development of a general relativistic formalism that allows one to analytically express the mass and spin parameters of the Kerr black hole in terms of observational data: the total redshift and blueshift of photons emitted by massive geodesic particles revolving the black hole and their orbital parameters. Thus, we present concise closed formulas for the mass and spin parameters of the Kerr black hole in terms of few directly observed quantities in the case of equatorial circular orbits either when the black hole is static or is moving with respect to a distant observer. Furthermore, we incorporate the gravitational dragging effect generated by the rotating nature of the Kerr black hole into the analysis and elucidate its nontrivial contribution to the expression for the light bending parameter and the frequency shifts of photons emitted by orbiting particles that renders simple symmetric expressions for the kinematic redshift and blueshift. We also incorporate the dependency of the frequency shift on the azimuthal angle, a fact that allows one to express the total redshift/blueshift at any point of the orbit of the revolving particle for the cases when the black hole is both static or moving with respect to us. These formulas allow one to compute the Kerr black hole parameters by applying this general relativistic formalism to astrophysical systems like the megamaser accretion disks orbiting supermassive black holes at the core of active galactic nuclei. Our results open a new window to implement parameter estimation studies to constrain black hole variables, and they can be generalized to black hole solutions beyond Einstein's gravity.

Toward the Gravitational Redshift Detection in NGC 4258 and the Estimation of Its Black Hole Mass-to-distance Ratio

Abstract We construct from first principles a general relativistic approach to study Schwarzschild black hole (BH) rotation curves and estimate the mass-to-distance ratio of the active galactic nucleus of NGC 4258 in terms of astrophysical observable quantities. The presented method allows one to clearly distinguish and quantify the general and special relativistic contributions to the total redshift expression. The total relativistic redshift/blueshift comprises three components: the gravitational redshift due to the spacetime curvature generated by the mass of the BH in its vicinity, the kinematic shift, originated by the photons’ local Doppler effect, and the redshift due to a special relativistic boost that describes the motion of a galaxy from a distant observer. We apply our method to the largest data set of highly redshifted water megamaser measurements on the accretion disk of the NGC 4258 active galaxy and use this general relativistic method to estimate its BH mass-to-distance ratio: M/D = (0.5326 ± 0.00022) × 107 M ⊙ Mpc−1.

Forward Modeling Populations of Flares from Tidal Disruptions of Stars by Supermassive Black Holes

Abstract Detections of the tidal disruption flares (TDFs) of stars by supermassive black holes (SMBHs) are rapidly accumulating as optical surveys improve. These detections may provide constraints on SMBH demographics, stellar dynamics, and stellar evolution in galaxies. To maximize this scientific impact, we require a better understanding of how astrophysical parameters interact with survey selection effects in setting the properties of detected flares. We develop a framework for modeling the distributions of optical TDF detections in surveys across attributes of the host galaxies and the flares themselves. This model folds in effects of the stellar disruption rate in each galaxy, the flare luminosity and temperature distributions, the effects of obscuration and reddening by dust in the host galaxy, and survey selection criteria. We directly apply this model to the sample of TDFs detected by the Zwicky Transient Facility, and find that the overall flare detection rate is in line with simple theoretical expectation. The model can also reproduce the distribution of total stellar mass and redshift of the host galaxies, but fails to match all details of the detected flares, such as their luminosity and temperature distributions. We also find that dust obscuration likely plays an important role in suppressing the TDF detection rate in star-forming galaxies. While we do not find that the unusual preference of TDFs to have hosts in post-starburst galaxies in the “green valley” can be entirely explained by selection effects, our model can help to quantify the true rate enhancement in those galaxies.

Quantitative assessing of crystal field, nephelauxetic, and Stokes shift effects on the blue luminescence of Eu2+ ions incorporated in ZnS films

A quantitative study of the crystal field, nephelauxetic, and Stokes shift effects on the 5d → 4 f levels of Eu2+ ions incorporated in ZnS films is presented. The magnitude of the crystal effect was calculated using the simplest point charge model to express the crystal field splitting of Eu2+ 5d orbitals surrounded by four S2− ligands in tetrahedral coordination symmetry. The shift of the centroid of the 5d levels by nephelauxetic effect was analyzed using a model that involves the polarizability of the anion ligands, similar to that used to investigate this effect for Ce3+ in many inorganic compounds. The Stokes shift was evaluated according to the Frank-Condon principle, under the idealized situation where the Stokes shift and the emission bandwidth can be expressed in terms of the Huang-Rhys parameter. We found that the redshift of the 5d → 4 f transition for the free Eu2+ ion, due to crystal field splitting was half of the redshift due to the nephelauxetic effect. This result is consistent with the large size, large polarizability, and low electronegativity of the sulfide ions. We also found a relatively large Stokes shift which can be attributed to the autoionization of the 5d electrons to the conduction band levels. The total redshift of the 5d and 4 f energy levels with respect to the 5d and 4 f energy gap for a free Eu2+ in vacuum fits quite well with the blue luminescence peaked at 2.73 eV for Eu2+ ions incorporated in the ZnS films. Based on the experimental results and the calculations for the crystal field splitting, nephelauxetic, and Stokes shift effects, we also propose a simplified energy band and levels diagram which helps to explain the excitation-emission mechanisms of the blue luminescence of the Eu2+ ions incorporated in the ZnS films.

Cosmology and the massive photon frequency shift in the Standard-Model Extension

The total red shift z might be recast as a combination of the expansion red shift and a static shift due to the energy–momentum tensor non-conservation of a photon propagating through Electro-Magnetic (EM) fields. If massive, the photon may be described by the de Broglie–Proca (dBP) theory which satisfies the Lorentz(-Poincaré) Symmetry (LoSy) but not gauge-invariance. The latter is regained in the Standard-Model Extension (SME), associated with LoSy Violation (LSV) that naturally dresses photons of a mass. The non-conservation stems from the vacuum expectation value of the vector and tensor LSV fields. The final colour (red or blue) and size of the static shift depend on the orientations and strength of the LSV and EM multiple fields encountered along the path of the photon. Turning to cosmology, for a zero Omega _{Lambda } energy density, the discrepancy between luminosity and red shift distances of SNeIa disappears thanks to the recasting of z. Massive photons induce an effective dark energy acting ‘optically’ but not dynamically.

Redshift Anomaly of the 2292 MHz Radio Signal Emitted by the Pioneer-6 Space Probe as Multiple Interactions with Photo-Ionized Electrons in the Solar Corona

This paper calculates the redshift of the 2292 MHz radio photon emitted by the Pioneer-6 space probe. The signal crossed the solar corona on the days close to the solar occultation between November and December 1968, the only ones for which scientific data are available, until it reached a terrestrial radio receiver. The specific study is based on a calculated orbital model of the Earth and Pioneer-6 system made on a scale of 1:100,000 by a CAD, on the New Tired Light theory adapted to the geometric and physical configuration of the topic and on a computational method. Removing the Doppler shift contributions of proper and rotational motions, due to the set-up of the receiver, and excluding the recombination factor of neutral hydrogen, which is irrelevant for distances within 1 AU, the calculation of the redshift can be traced back to the interactions between the radio signal and the electrons of the solar corona alone. The latter are contained in a Stroemgren sphere and photo-ionized by solar radiation in the UV and X-ray range. Furthermore, in order to have an interactional redshift contribution, the electrons have to satisfy the Wigner-Crystal Precondition for which their unitary potential energy is greater than their kinetic energy. Otherwise, a Thomson scattering process takes place in which the energy of the radio photon remains unchanged. The comparison between the gravitational redshift together with the interactional redshift detected from this study methodology and the total redshift obtained from other scientific studies shows a similarity between the curves, including the observational data, both in terms of values, trend of the graphs and single punctual variations.

A massive blow for ΛCDM – the high redshift, mass, and collision velocity of the interacting galaxy cluster El Gordo contradicts concordance cosmology

ABSTRACT El Gordo (ACT-CL J0102-4915) is an extremely massive galaxy cluster (M200 ≈ 3 × 1015 M⊙) at redshift z = 0.87 composed of two subclusters with a mass ratio of 3.6 merging at speed Vinfall ≈ 2500 km s−1. Such a fast collision between individually rare massive clusters is unexpected in Lambda cold dark matter (ΛCDM) cosmology at such high z. However, this is required for non-cosmological hydrodynamical simulations of the merger to match its observed properties. Here, we determine the probability of finding a similar object in a ΛCDM context using the Jubilee simulation box with a side length of $6 \, h^{-1}$ Gpc. We search for galaxy cluster pairs that have turned around from the cosmic expansion with properties similar to El Gordo in terms of total mass, mass ratio, redshift, and collision velocity relative to virial velocity. We fit the distribution of pair total mass quite accurately, with the fits used in two methods to infer the probability of observing El Gordo in the surveyed region. The more conservative (and detailed) method involves considering the expected distribution of pairwise mass and redshift for analogue pairs with similar dimensionless parameters to El Gordo in the past light-cone of a z = 0 observer. Detecting one pair with its mass and redshift rules out ΛCDM cosmology at 6.16σ. We also use the results of Kraljic and Sarkar to show that the Bullet Cluster is in 2.78σ tension once the sky coverage of its discovery survey is accounted for. Using a χ2 approach, the combined tension can be estimated as 6.43σ. Both collisions arise naturally in a Milgromian dynamics (MOND) cosmology with light sterile neutrinos.

A successful search for intervening 21 cm H i absorption in galaxies at 0.4 < z <1.0 with the Australian square kilometre array pathfinder (ASKAP)

ABSTRACT We have used the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope to search for intervening 21 cm neutral hydrogen (H i) absorption along the line of sight to 53 bright radio continuum sources. Our observations are sensitive to H i column densities typical of Damped Lyman Alpha absorbers (DLAs) in cool gas with an H i spin temperature below about 300–500 K. The six-dish Boolardy Engineering Test Array (BETA) and twelve-antenna Early Science array (ASKAP-12) covered a frequency range corresponding to redshift 0.4 < z < 1.0 and 0.37 < z < 0.77, respectively, for the H i line. Fifty of the 53 radio sources observed have reliable optical redshifts, giving a total redshift path Δz = 21.37. This was a spectroscopically untargeted survey, with no prior assumptions about the location of the lines in redshift space. Four intervening H i lines were detected, two of them new. In each case, the estimated H i column density lies above the DLA limit for H i spin temperatures above 50–80 K, and we estimate a DLA number density at redshift z ∼ 0.6 of $n(z)=0.19^{+0.15 }_{ -0.09}$. This value lies somewhat above the general trend of n(z) with redshift seen in optical DLA studies. Although the current sample is small, it represents an important proof of concept for the much larger 21 cm First Large Absorption Survey in H i (FLASH) project to be carried out with the full 36-antenna ASKAP telescope, probing a total redshift path $\Delta z\sim \, 50,000$.

The evolution of neutral hydrogen over the past 11 Gyr via H i 21 cm absorption

ABSTRACT We present the results of a blind search for intervening H i 21 cm absorption towards 260 radio sources in the redshift range 0 < z < 2.74 with the Green Bank Telescope. The survey has the sensitivity to detect sub-damped Ly α (DLA) systems for H i spin temperatures Ts/f = 100 K, and despite the successful re-detection of 10 known 21 cm absorbers in the sample, we detect no new absorption lines in the full survey. Sources detected in 21 cm absorption were also searched for hydroxyl (OH) 18 cm absorption and we re-detect 1667 MHz OH absorption towards PKS 1830-211. We searched for intervening H i 21 cm absorption along the line of sight in each source achieving a total redshift coverage of Δz = 88.64 (comoving absorption path of ΔX = 159.5) after removing regions affected by radio frequency interference. We compute a 95 per cent confidence upper limit on the column density frequency distribution f(NH i) and set a statistical constraint on the spin temperature Ts in the range 100–1000 K, consistent with prior redshifted optical DLA surveys and H i 21 cm emission observations at the same redshifts. We infer a value for the cosmological mass density of neutral gas, ΩH i. Through comparison with prior ΩH i measurements, we place a statistical constraint on the mean spin temperature of Ts/f = 175 K. Our derived ΩH i values support a relative mild evolution in ΩH i over the last 11 Gyr and are consistent with other methods that measure ΩH i.

The Cosmic Ultraviolet Baryon Survey (CUBS) – I. Overview and the diverse environments of Lyman limit systems at z < 1

ABSTRACT We present initial results from the Cosmic Ultraviolet Baryon Survey (CUBS). CUBS is designed to map diffuse baryonic structures at redshift z ≲ 1 using absorption-line spectroscopy of 15 UV-bright QSOs with matching deep galaxy survey data. CUBS QSOs are selected based on their NUV brightness to avoid biases against the presence of intervening Lyman limit systems (LLSs) at zabs < 1. We report five new LLSs of $\log \, N({\mathrm{ H} \,{\small I}})/{{\rm cm^{-2}}}\gtrsim 17.2$ over a total redshift survey path-length of $\Delta \, z_{\mathrm{ LL}}=9.3$, and a number density of $n(z)=0.43_{-0.18}^{+0.26}$. Considering all absorbers with $\log \, N({{\mathrm{ H} \,{\small I}}})/{{\rm cm^{-2}}}\gt 16.5$ leads to $n(z)=1.08_{-0.25}^{+0.31}$ at zabs < 1. All LLSs exhibit a multicomponent structure and associated metal transitions from multiple ionization states such as C ii, C iii, Mg ii, Si ii, Si iii, and O vi absorption. Differential chemical enrichment levels as well as ionization states are directly observed across individual components in three LLSs. We present deep galaxy survey data obtained using the VLT-MUSE integral field spectrograph and the Magellan Telescopes, reaching sensitivities necessary for detecting galaxies fainter than $0.1\, L_*$ at d ≲ 300 physical kpc (pkpc) in all five fields. A diverse range of galaxy properties is seen around these LLSs, from a low-mass dwarf galaxy pair, a co-rotating gaseous halo/disc, a star-forming galaxy, a massive quiescent galaxy, to a galaxy group. The closest galaxies have projected distances ranging from d = 15 to 72 pkpc and intrinsic luminosities from ${\approx} 0.01\, L_*$ to ${\approx} 3\, L_*$. Our study shows that LLSs originate in a variety of galaxy environments and trace gaseous structures with a broad range of metallicities.

Detecting helium reionization with fast radio bursts

Fast radio bursts (FRB) probe the electron density of the universe along the path of propagation, making high redshift FRB sensitive to the helium reionization epoch. We analyze the signal to noise with which a detection of the amplitude of reionization can be made, and its redshift, for various cases of future FRB survey samples, assessing survey characteristics including total number, redshift distribution, peak redshift, redshift depth, and number above the reionization redshift, as well as dependence on reionization redshift. We take into account scatter in the dispersion measure due to an inhomogeneous intergalactic medium (IGM) and uncertainty in the FRB host and environment dispersion measure, as well as cosmology. For a future survey with 500 FRB extending out to $z=5$, and a sudden reionization, the detection of helium reionization can approach the $5\sigma$ level and the reionization redshift be determined to $\sigma(z_r)\approx0.24$ in an optimistic scenario, or $2\sigma$ and $\sigma(z_r)\approx0.34$ taking into account further uncertainties on IGM fraction evolution and redshift uncertainties.

Study of galaxy clusters as standard bucket using Chandra X-ray satellite data

Clusters of galaxies are the most massive structures in the Universe, confined together in gravitationally bound systems with typical mass in the range of 1013 M⊙−1015 M⊙. Clusters of galaxies may be considered as self-similar, meaning that the properties of low mass clusters can be scaled up from the properties of more massive clusters, and vice versa. Clusters of galaxies have been thought to have standard mass fraction of gas, independent of their redshifts or total masses, and therefore proposed to be used as “standard buckets”.The purpose of this work is to check the validity of clusters of galaxies as standard buckets by studying larger sample than those analysed by Mantz et al. (2014). The data set employed here consists of Chandra observations of 47 relaxed clusters at redshift 0.069 ≤ z ≤ 1.063. The results of this study show that compared to the differential gas fraction (fgas,diff), the cumulative gas mass fractions (fgas,2500) of the total sample of clusters are less dependent to the total mass M2500 and redshift. Relation between gas mass fraction and total mass M2500 suggests that massive clusters are more reliable to be used as standard buckets.

Mass and Light of Abell 370: A Strong and Weak Lensing Analysis

Abstract We present a new gravitational lens model of the Hubble Frontier Fields cluster Abell 370 (z = 0.375) using imaging and spectroscopy from Hubble Space Telescope and ground-based spectroscopy. We combine constraints from a catalog of 909 weakly lensed galaxies and 39 multiply imaged sources comprised of 114 multiple images, including a system of multiply imaged candidates at z = 7.84 ± 0.02, to obtain a best-fit mass distribution using the cluster lens modeling code Strong and Weak Lensing United. As the only analysis of A370 using strong and weak lensing constraints from Hubble Frontier Fields data, our method provides an independent check of assumptions on the mass distribution used in other methods. Convergence, shear, and magnification maps are made publicly available through the HFF website (http://www.stsci.edu/hst/campaigns/frontier-fields). We find that the model we produce is similar to models produced by other groups, with some exceptions due to the differences in lensing code methodology. In an effort to study how our total projected mass distribution traces light, we measure the stellar mass density distribution using Spitzer/Infrared Array Camera imaging. Comparing our total mass density to our stellar mass density in a radius of 0.3 Mpc, we find a mean projected stellar to total mass ratio of (stat.) using the diet Salpeter initial mass function. This value is in general agreement with independent measurements of in clusters of similar total mass and redshift.

Mass-metallicity relation of dwarf galaxies and its dependency on time: clues from resolved systems and comparison with massive galaxies

We present a new approach to study the mass-metallicity relation and its dependency on time. We used the star formation history (SFH) derived from color-magnitude diagram fitting techniques of a sample of Local Group (LG) dwarfs to obtain stellar masses, metallicities, and star-formation rates (SFR) to analyze the mass-metallicity relation as a function of the ages of their stellar populations. The accurate SFHs allow a time resolution of about 2 Gyr at the oldest ages for a total redshift range of 0<~z<~3. The mass-metallicity relation retrieved for the sample of LG dwarfs was compared with a large dataset of literature data obtained in a wide redshift range. Neither of the two independent datasets shows a clear evolution of the mass-metallicity relation slope with redshift. However, when the star-formation rate is added as an additional parameter in the relation, it shows a dependence on the redshift in the sense that the coefficient of the mass decreases with increasing redshift, while the coefficient for the SFR is almost constant with time. This result suggests an increasing contribution with time of the galaxy stellar mass to the metalliticy of the stars that formed most recently, but it also shows that the SFR can play a fundamental role in shaping the mass-metallicity relation.

New Source of the Red Shift of Highly-Excited Hydrogenic Spectral Lines in Astrophysical and Laboratory Plasmas

High-n hydrogen spectral lines (SL), n=13–17, studied in astrophysical and laboratory observations at the electron density Ne ~ 1013 cm-3 by Bengtson and Chester exhibited red shifts by orders of magnitude greater than the theoretical shifts known up to now. Specifically, BC presented the shifts of these SL observed in the spectra from Sirius and in the spectra from a radiofrequency discharge plasma in the laboratory: both types of the observations yielded red shifts that exceeded the corresponding theoretical shifts by orders of magnitude. In the present paper we introduce an additional source of the shift of high-n hydrogenic SL. We show that for high-n hydrogen SL it makes the primary contribution to the total red shift. We demonstrate that for the conditions of the astrophysical and laboratory observations from paper by Bengtson and Chester, this additional red shift is by orders of magnitude greater than the theoretical shifts known up to now. Finally we show that the allowance for this additional red shift removes the existed huge discrepancy between the observed and theoretical shifts of those that of high-n hydrogen SL.

STAR FORMATION IN INTERMEDIATE REDSHIFT 0.2 &lt; z &lt; 0.7 BRIGHTEST CLUSTER GALAXIES

ABSTRACT We present a multi-wavelength photometric and spectroscopic study of 42 Brightest Cluster Galaxies (BCGs) in two samples of galaxy clusters chosen for a gravitational lensing study. The study’s initial sample combines 25 BCGs from the Cluster Lensing and Supernova Survey with Hubble sample and 37 BCGs from the Sloan Giant Arcs Survey with a total redshift range of Using archival GALEX, Hubble Space Telescope, Wide-Field Infrared Survey Explorer, Herschel, and Very Large Array data we determine the BCGs’ stellar mass, radio power, and star formation rates. The radio power is higher than expected if due to star formation, consistent with the BCGs being active galactic nucleus (AGN)-powered radio sources. This suggests that the AGN and star formation are both fueled by cold gas in the host galaxy. The specific star formation rate (sSFR) is low and constant with redshift. The mean sSFR is 9.42 × 10−12 yr−1, which corresponds to a mass doubling time of 105 billion years. These findings are consistent with models for hierarchical formation of BCGs, which suggest that star formation is no longer a significant channel for galaxy growth for z 1. Instead, stellar growth (of the order of a factor of at least two) during this period is expected to occur mainly via minor dry mergers.