scholarly journals Optimizing gravitational waves follow-up using galaxies stellar mass

2020 ◽  
Vol 492 (4) ◽  
pp. 4768-4779 ◽  
Author(s):  
J-G Ducoin ◽  
D Corre ◽  
N Leroy ◽  
E Le Floch
Keyword(s):  
Gravitational Wave ◽  
Stellar Mass ◽  
Host Galaxy ◽  
New Approach ◽  
Massive Galaxies ◽  
New Strategy ◽  
The Galaxy ◽  
Wave Event ◽  
Stellar Masses

ABSTRACT We present a new strategy to optimize the electromagnetic follow-up of gravitational wave triggers. This method is based on the widely used galaxy targeting approach where we add the stellar mass of galaxies in order to prioritize the more massive galaxies. We cross-matched the Galaxy List for the Advanced Detector Era (GLADE) galaxy catalogue with the AllWISE catalogue up to 400 Mpc with an efficiency of ∼93 per cent, and derived stellar masses using a mass-to-light ratio using the WISE1 band luminosity. We developed a new grade to rank galaxies combining their 3D localization probability associated with the gravitational wave event with the new stellar mass information. The efficiency of this new approach is illustrated with the GW170817 event, which shows that its host galaxy, NGC 4993, is ranked at the first place using this new method. The catalogue, named MANGROVE, is publicly available and the ranking of galaxies is automatically provided through a dedicated website for each gravitational wave event.

scholarly journals Characterization of peculiar early-type galaxies in the local universe

2012 ◽  
Vol 10 (H16) ◽  
pp. 333-333
Author(s):  
Beatriz H. F. Ramos ◽  
Karín Menéndez-Delmestre ◽  
Taehyun Kim ◽  
Kartik Sheth ◽  
Keyword(s):  
Star Formation ◽  
Broad Band ◽  
Stellar Populations ◽  
Stellar Mass ◽  
Stellar Structure ◽  
Host Galaxy ◽  
Early Type ◽  
Local Universe ◽  
The Galaxy ◽  
Stellar Masses

AbstractEarly-type galaxies (ETGs) have been characterized as objects dominated by old stellar populations, containing little or no cold gas and dust, and thus, non-existent star formation. However, there are indications in the literature that some ETGs deviate from this: some have significant amounts of gas and dust, are forming stars, and/or display stellar substructures (tidal features, disks or shells, e.g., Kormendy et al. 1997, Rix, Carollo & Freeman 1999). A better understanding of the evolution of ETGs and the details of their “peculiarities” is critical to properly constrain models of galaxy formation. We present preliminary results on a photometric analysis of substructures in local ETGs, based on 3.6μm IRAC images from the Spitzer Survey of Stellar Structure in Galaxies (S4G; Sheth et al. 2010), which comprises one of the largest mid-IR photometric surveys of the local Universe. Relatively unhindered by extinction and dominated by the low-mass stellar populations that dominate a galaxy's stellar mass budget, the IR is the ideal waveband to trace the details of stellar structures in galaxies. Based on 2D GALFIT (Peng et al. 2002) decomposition, we find tidal features in 17% of 146 ETGs from S4G. For both the GALFIT model and the galaxy residual images, we calculate the total counts inside an annular region centered on the galaxy, where the inner radius is the effective radius of the galaxy. Assuming that a tidal feature and its host galaxy have the same mass-to-luminosity ratio (M/L), the ratio of the residual counts over model counts translates into the ratio of their stellar masses. We find that the tidal features in the majority of peculiar ETGs in our sample account for no more than 11% of the galaxy's total stellar mass. Considering that simulations (Canalizo et al. 2007) suggest an upper limit in relative stellar mass of 25% for shells resulting from a past major merger, the values we find support a merger origin. We are in the process of applying the decomposition method to GALEX UV images and optical SDSS images of these peculiar ETGs in order to characterize the underlying substructure and provide constraints on astrophysical properties such as star formation rates and stellar masses associated to these tidal features, based on broad-band SED template fitting techniques.

scholarly journals Emerge: Empirical predictions of galaxy merger rates since z ∼ 6

2020 ◽  
Author(s):  
Joseph A O’Leary ◽  
Benjamin P Moster ◽  
Thorsten Naab ◽  
Rachel S Somerville
Keyword(s):  
Galaxy Formation ◽  
Power Law ◽  
Stellar Mass ◽  
Direct Result ◽  
Mass Relation ◽  
Massive Galaxies ◽  
The Galaxy ◽  
Major Merger ◽  
Low Mass ◽  
Merger Rate

Abstract We explore the galaxy-galaxy merger rate with the empirical model for galaxy formation, emerge. On average, we find that between 2 per cent and 20 per cent of massive galaxies (log10(m*/M⊙) ≥ 10.3) will experience a major merger per Gyr. Our model predicts galaxy merger rates that do not scale as a power-law with redshift when selected by descendant stellar mass, and exhibit a clear stellar mass and mass-ratio dependence. Specifically, major mergers are more frequent at high masses and at low redshift. We show mergers are significant for the stellar mass growth of galaxies log10(m*/M⊙) ≳ 11.0. For the most massive galaxies major mergers dominate the accreted mass fraction, contributing as much as 90 per cent of the total accreted stellar mass. We reinforce that these phenomena are a direct result of the stellar-to-halo mass relation, which results in massive galaxies having a higher likelihood of experiencing major mergers than low mass galaxies. Our model produces a galaxy pair fraction consistent with recent observations, exhibiting a form best described by a power-law exponential function. Translating these pair fractions into merger rates results in an inaccurate prediction compared to the model intrinsic values when using published observation timescales. We find the pair fraction can be well mapped to the intrinsic merger rate by adopting an observation timescale that decreases linearly with redshift as Tobs = −0.36(1 + z) + 2.39 [Gyr], assuming all observed pairs merge by z = 0.

scholarly journals Realistic mock observations of the sizes and stellar mass surface densities of massive galaxies in FIRE-2 zoom-in simulations

2020 ◽  
Vol 501 (2) ◽  
pp. 1591-1602
Author(s):  
T Parsotan ◽  
R K Cochrane ◽  
C C Hayward ◽  
D Anglés-Alcázar ◽  
R Feldmann ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Surface Density ◽  
Stellar Mass ◽  
Massive Galaxies ◽  
Star Forming ◽  
Stellar Feedback ◽  
Central Surface ◽  
Stellar Ages ◽  
The Galaxy ◽  
Zoom In

ABSTRACT The galaxy size–stellar mass and central surface density–stellar mass relationships are fundamental observational constraints on galaxy formation models. However, inferring the physical size of a galaxy from observed stellar emission is non-trivial due to various observational effects, such as the mass-to-light ratio variations that can be caused by non-uniform stellar ages, metallicities, and dust attenuation. Consequently, forward-modelling light-based sizes from simulations is desirable. In this work, we use the skirt  dust radiative transfer code to generate synthetic observations of massive galaxies ($M_{*}\sim 10^{11}\, \rm {M_{\odot }}$ at z = 2, hosted by haloes of mass $M_{\rm {halo}}\sim 10^{12.5}\, \rm {M_{\odot }}$) from high-resolution cosmological zoom-in simulations that form part of the Feedback In Realistic Environments project. The simulations used in this paper include explicit stellar feedback but no active galactic nucleus (AGN) feedback. From each mock observation, we infer the effective radius (Re), as well as the stellar mass surface density within this radius and within $1\, \rm {kpc}$ (Σe and Σ1, respectively). We first investigate how well the intrinsic half-mass radius and stellar mass surface density can be inferred from observables. The majority of predicted sizes and surface densities are within a factor of 2 of the intrinsic values. We then compare our predictions to the observed size–mass relationship and the Σ1−M⋆ and Σe−M⋆ relationships. At z ≳ 2, the simulated massive galaxies are in general agreement with observational scaling relations. At z ≲ 2, they evolve to become too compact but still star forming, in the stellar mass and redshift regime where many of them should be quenched. Our results suggest that some additional source of feedback, such as AGN-driven outflows, is necessary in order to decrease the central densities of the simulated massive galaxies to bring them into agreement with observations at z ≲ 2.

scholarly journals The Bimodality of Galaxy Populations Revisited Through Spectral Synthesis

2006 ◽  
Vol 2 (S235) ◽  
pp. 139-139
Author(s):  
L. Sodré ◽  
A. Mateus ◽  
R. Cid Fernandes ◽  
G. Stasińska ◽  
W. Schoenell ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Spectral Synthesis ◽  
Synthesis Method ◽  
Local Universe ◽  
Massive Galaxies ◽  
Star Forming ◽  
The Galaxy ◽  
Galaxy Populations ◽  
Galaxy Population ◽  
Stellar Masses

AbstractWe revisit the bimodality of the galaxy population seen in the local universe. We address this issue in terms of physical properties of galaxies, such as mean stellar ages and stellar masses, derived from the application of a spectral synthesis method to galaxy spectra from the SDSS. We show that the mean light-weighted stellar age of galaxies presents the best description of the bimodality seen in the galaxy population. The stellar mass has an additional role since most of the star-forming galaxies present in the local universe are low-mass galaxies. Our results give support to the existence of a ‘downsizing’ in galaxy formation, where nowadays massive galaxies tend to have stellar populations older than those found in less massive objects.

scholarly journals The XXL Survey

2018 ◽  
Vol 620 ◽  
pp. A7 ◽  
Author(s):  
V. Guglielmo ◽  
B. M. Poggianti ◽  
B. Vulcani ◽  
C. Adami ◽  
F. Gastaldello ◽  
...  
Keyword(s):  
Mass Function ◽  
Stellar Mass ◽  
X Ray ◽  
Field Versus ◽  
Final Sample ◽  
Wide Range ◽  
The Galaxy ◽  
Halo Masses ◽  
Stellar Masses ◽  
Physical Phenomena

Context. The fraction of galaxies bound in groups in the nearby Universe is high (50% at z ~ 0). Systematic studies of galaxy properties in groups are important in order to improve our understanding of the evolution of galaxies and of the physical phenomena occurring within this environment. Aims. We have built a complete spectrophotometric sample of galaxies within X-ray detected, optically spectroscopically confirmed groups and clusters (G&C), covering a wide range of halo masses at z ≤ 0.6. Methods. In the context of the XXL survey, we analyse a sample of 164 G&C in the XXL-North region (XXL-N), at z ≤ 0.6, with a wide range of virial masses (1.24 × 1013 ≤ M500,scal(M⊙) ≤ 6.63 × 1014) and X-ray luminosities ((2.27 × 1041 ≤ L500,scalXXL(erg s−1) ≤ 2.15 × 1044)). The G&C are X-ray selected and spectroscopically confirmed. We describe the membership assignment and the spectroscopic completeness analysis, and compute stellar masses. As a first scientific exploitation of the sample, we study the dependence of the galaxy stellar mass function (GSMF) on global environment. Results. We present a spectrophotometric characterisation of the G&C and their galaxies. The final sample contains 132 G&C, 22 111 field galaxies and 2225 G&C galaxies with r-band magnitude <20. Of the G&C, 95% have at least three spectroscopic members, and 70% at least ten. The shape of the GSMF seems not to depend on environment (field versus G&C) or X-ray luminosity (used as a proxy for the virial mass of the system). These results are confirmed by the study of the correlation between mean stellar mass of G&C members and L500,scalXXL. We release the spectrophotometric catalogue of galaxies with all the quantities computed in this work. Conclusions. As a first homogeneous census of galaxies within X-ray spectroscopically confirmed G&C at these redshifts, this sample will allow environmental studies of the evolution of galaxy properties.

scholarly journals Emission-line properties of the most luminous AGNs in massive galaxies at intermediate redshifts

2019 ◽  
Vol 489 (2) ◽  
pp. 1973-1985 ◽  
Author(s):  
Guinevere Kauffmann ◽  
Claudia Maraston
Keyword(s):  
Emission Line ◽  
Galactic Nuclei ◽  
Uniform Density ◽  
Type Ii ◽  
Ionized Gas ◽  
Massive Galaxies ◽  
The Galaxy ◽  
Gaussian Fit ◽  
Stellar Masses ◽  
Intermediate Redshifts

ABSTRACT We have analysed the emission-line properties of 6019 Type II active galactic nuclei (AGNs) at redshifts in the range 0.4–0.8 with [O iii] luminosities greater than $3 \times 10^8 \, \mathrm{L}_{\odot }$, characteristic of the Type II quasars first identified in population studies by Zakamska et al. The AGNs are drawn from the CMASS sample of galaxies with stellar masses greater than $10^{11} \, \mathrm{M}_{\odot }$ that were studied as part of the Baryon Oscillation Spectroscopic Survey (BOSS) and comprise 0.5 per cent of the total population of these galaxies. Individual spectra have low S/N, so the analysis is carried out on stacked spectra in bins of [O iii] luminosity and estimated stellar age. The emission line ratios of the stacks are well fit with simple uniform-density photoionization models with metallicities between solar and twice solar. In the stacks, a number of emission lines are found to have distinct broad components requiring a double Gaussian rather than a single Gaussian fit, indicative of outflowing ionized gas. These are: [O iii] λ4959, [O iii] λ5007, [O ii] λ3727,3729, and H αλ6563. Higher ionization lines such as [Ne iii] λ3869 and [Ne v] λ3345 are detected in the stacks, but are well fit by single Gaussians. The broad components typically contain a third of the total line flux and have widths of 600 km s−1 for the oxygen lines and 900 km s−1 for H α. The fraction of the flux in the broad component and its width are independent of [O iii] luminosity, stellar age, radio, and mid-IR luminosity. The stellar mass of the galaxy is the only parameter we could identify that influences the width of the broad line component.

scholarly journals Strong lensing as a giant telescope to localize the host galaxy of gravitational wave event

2020 ◽  
Vol 497 (1) ◽  
pp. 204-209 ◽  
Author(s):  
Hai Yu ◽  
Pengjie Zhang ◽  
Fa-Yin Wang
Keyword(s):  
Gravitational Wave ◽  
Host Galaxy ◽  
Observational Constraints ◽  
Host Galaxies ◽  
Einstein Telescope ◽  
Strong Lensing ◽  
Potential Applications ◽  
Wave Event ◽  
Localization Uncertainty ◽  
Better Than

ABSTRACT Standard siren cosmology of gravitational wave (GW) merger events relies on the identification of host galaxies and their redshifts. But this can be highly challenging due to numerous candidates of galaxies in the GW localization area. We point out that the number of candidates can be reduced by orders of magnitude for strongly lensed GW events, due to extra observational constraints. For the next-generation GW detectors like Einstein Telescope (ET), we estimate that this number is usually significantly less than one, as long as the GW localization uncertainty is better than $\sim 10\, \rm deg^2$. This implies that the unique identification of the host galaxy of lensed GW event detected by ET and Cosmic Explorer (CE) is possible. This provides us a promising opportunity to measure the redshift of the GW event and facilitate the standard siren cosmology. We also discuss its potential applications in understanding the evolution process and environment of the GW event.

scholarly journals xGASS: the role of bulges along and across the local star-forming main sequence

2020 ◽  
Vol 493 (4) ◽  
pp. 5596-5605 ◽  
Author(s):  
Robin H W Cook ◽  
Luca Cortese ◽  
Barbara Catinella ◽  
Aaron Robotham
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Formation Rate ◽  
Stellar Mass ◽  
Local Universe ◽  
Star Forming ◽  
Star Formation Activity ◽  
The Galaxy ◽  
Stellar Masses

ABSTRACT We use our catalogue of structural decomposition measurements for the extended GALEX Arecibo SDSS Survey (xGASS) to study the role of bulges both along and across the galaxy star-forming main sequence (SFMS). We show that the slope in the sSFR–M⋆ relation flattens by ∼0.1 dex per decade in M⋆ when re-normalizing specifice star formation rate (sSFR) by disc stellar mass instead of total stellar mass. However, recasting the sSFR–M⋆ relation into the framework of only disc-specific quantities shows that a residual trend remains against disc stellar mass with equivalent slope and comparable scatter to that of the total galaxy relation. This suggests that the residual declining slope of the SFMS is intrinsic to the disc components of galaxies. We further investigate the distribution of bulge-to-total ratios (B/T) as a function of distance from the SFMS (ΔSFRMS). At all stellar masses, the average B/T of local galaxies decreases monotonically with increasing ΔSFRMS. Contrary to previous works, we find that the upper envelope of the SFMS is not dominated by objects with a significant bulge component. This rules out a scenario in which, in the local Universe, objects with increased star formation activity are simultaneously experiencing a significant bulge growth. We suggest that much of the discrepancies between different works studying the role of bulges originate from differences in the methodology of structurally decomposing galaxies.

scholarly journals A systematic search for galaxy proto-cluster cores at z ∼ 2

2020 ◽  
Vol 496 (3) ◽  
pp. 3169-3181
Author(s):  
Makoto Ando ◽  
Kazuhiro Shimasaku ◽  
Rieko Momose
Keyword(s):  
Galaxy Formation ◽  
Mass Range ◽  
Mass Function ◽  
Stellar Mass ◽  
Dark Matter Halo ◽  
Massive Galaxies ◽  
Quenching Efficiency ◽  
The Galaxy ◽  
Mass Assembly ◽  
Cluster Cores

ABSTRACT A proto-cluster core is the most massive dark matter halo (DMH) in a given proto-cluster. To reveal the galaxy formation in core regions, we search for proto-cluster cores at z ∼ 2 in ${\sim}1.5\, \mathrm{deg}^{2}$ of the COSMOS field. Using pairs of massive galaxies [log (M*/M⊙) ≥ 11] as tracers of cores, we find 75 candidate cores, among which 54 per cent are estimated to be real. A clustering analysis finds that these cores have an average DMH mass of $2.6_{-0.8}^{+0.9}\times 10^{13}\, \mathrm{M}_{\odot }$, or $4.0_{-1.5}^{+1.8}\, \times 10^{13} \, \mathrm{M}_{\odot }$ after contamination correction. The extended Press–Schechter model shows that their descendant mass at z = 0 is consistent with Fornax-like or Virgo-like clusters. Moreover, using the IllustrisTNG simulation, we confirm that pairs of massive galaxies are good tracers of DMHs massive enough to be regarded as proto-cluster cores. We then derive the stellar mass function (SMF) and the quiescent fraction for member galaxies of the 75 candidate cores. We find that the core galaxies have a more top-heavy SMF than field galaxies at the same redshift, showing an excess at log (M*/M⊙) ≳ 10.5. The quiescent fraction, $0.17_{-0.04}^{+0.04}$ in the mass range 9.0 ≤ log (M*/M⊙) ≤ 11.0, is about three times higher than that of field counterparts, giving an environmental quenching efficiency of $0.13_{-0.04}^{+0.04}$. These results suggest that stellar mass assembly and quenching are accelerated as early as z ∼ 2 in proto-cluster cores.

scholarly journals Probing binary neutron star mergers in dense environments using afterglow counterparts

2020 ◽  
Vol 639 ◽  
pp. A15
Author(s):  
Raphaël Duque ◽  
Paz Beniamini ◽  
Frédéric Daigne ◽  
Robert Mochkovitch
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Indirect Evidence ◽  
High Sensitivity ◽  
Small Sample ◽  
High Density ◽  
Binary Neutron Star ◽  
Delay Times ◽  
Wave Event

The only binary neutron star merger gravitational wave event with detected electromagnetic counterparts recorded to date is GRB170817A. This merger occurred in a rarefied medium with a density smaller than 10−3 − 10−2 cm−3. Since kicks are imparted to neutron star binaries upon formation, and due to their long delay times before merger, such low-density circum-merger media are generally expected. However, there is some indirect evidence for fast-merging or low-kick binaries, which would coalesce in denser environments. Nonetheless, present astronomical data are largely inconclusive on the possibility of these high-density mergers. We describe a method to directly probe this hypothetical population of high-density mergers through multi-messenger observations of binary neutron star merger afterglows, exploiting the high sensitivity of these signals to the density of the merger environment. This method is based on a sample of merger afterglows that has yet to be collected. Its constraining power is large, even with a small sample of events. We discuss the method’s limitations and applicability. In the upcoming era of third-generation gravitational wave detectors, this method’s potential will be fully realized as it will allow us to probe mergers that occurred soon after the peak of cosmic star formation, provided the follow-up campaigns are able to locate the sources.

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