Search

Start Over Subject galaxies Rights public
2371. Multiwavelength measurement of galaxy structure
ID:
ivo://CDS.VizieR/J/MNRAS/435/623
Title:
Multiwavelength measurement of galaxy structure
Short Name:
J/MNRAS/435/623
Date:
21 Oct 2021
Publisher:
CDS
Description:
We demonstrate a new multiwavelength technique for two-dimensional parametric modelling of galaxy surface-brightness profiles, which we have incorporated into the widely used software GALFIT. Our new method, named GALFITM, extends GALFIT3's current single-band fitting process by simultaneously using multiple images of the same galaxy to constrain a wavelength-dependent model. Each standard profile parameter may vary as a function of wavelength, with a user-definable degree of smoothness, from constant to fully free. The performance of GALFITM is evaluated by fitting elliptical Sersic profiles to ugriz imaging data for 4026 galaxies, comprising the original Sloan Digital Sky Survey (SDSS) imaging for 163 low-redshift (v<~7000km/s) galaxies and 3863 artificially redshifted (0.01<~z<~0.25) images of the same galaxies. Comparing results from single-band and multiband techniques, we show that GALFITM significantly improves the extraction of information, particularly from bands with low signal-to-noise ratio (e.g. u and z SDSS bands) when combined with higher signal-to-noise images. We also study systematic trends in the recovered parameters, particularly Sersic index, that appear when one performs measurements of the same galaxies at successively higher redshifts. We argue that it is vital that studies investigating the evolution of galaxy structure are careful to avoid or correct for these biases. The resulting multiband photometric structural parameters for our sample of 163 galaxies are provided. We demonstrate the importance of considering multiband measurements by showing that the Sersic indices of spiral galaxies increase to redder wavelengths, as expected for composite bulge-disc systems. Finally, for the ellipticals in our sample, which should be well represented by single-Sersic models, we compare our measured parameters to those from previous studies.
2372. Multiwavelength photometry of 34 galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/441/1017
Title:
Multiwavelength photometry of 34 galaxies
Short Name:
J/MNRAS/441/1017
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a comparison of the physical properties of a rest-frame 250um selected sample of massive, dusty galaxies from 0<z<5.3. Our sample comprises 29 high-redshift submillimetre galaxies (SMGs) from the literature, and 843 dusty galaxies at z<0.5 from the Herschel-ATLAS, selected to have a similar stellar mass to the SMGs. The z>1 SMGs have an average SFR of 390^+80^_-70_M_{sun}_/yr which is 110 times that of the low-redshift sample matched in stellar mass to the SMGs (SFR=3.3+/-0.2M_{sun}_/yr). The SMGs harbour a substantial mass of dust (1.2^+0.3^_-0.2_x10^9^M_{sun}_), compared to (1.6+/-0.1)x10^8^M_{sun}_ for low-redshift dusty galaxies. At low redshifts the dust luminosity is dominated by the diffuse ISM, whereas a large fraction of the dust luminosity in SMGs originates from star-forming regions. At the same dust mass SMGs are offset towards a higher SFR compared to the low-redshift H-ATLAS galaxies. This is not only due to the higher gas fraction in SMGs but also because they are undergoing a more efficient mode of star formation, which is consistent with their bursty star-formation histories. The offset in SFR between SMGs and low-redshift galaxies is similar to that found in CO studies, suggesting that dust mass is as good a tracer of molecular gas as CO.
2373. Multi-wavelength study of clusters of galaxies. II.
ID:
ivo://CDS.VizieR/J/ApJ/761/114
Title:
Multi-wavelength study of clusters of galaxies. II.
Short Name:
J/ApJ/761/114
Date:
21 Oct 2021
Publisher:
CDS
Description:
Galaxy clusters provide powerful laboratories for the study of galaxy evolution, particularly the origin of correlations of morphology and star formation rate (SFR) with density. We construct visible to MIR spectral energy distributions of galaxies in eight low-redshift (z<0.3) clusters and use them to measure stellar masses and SFRs as a function of environment. A partial correlation analysis indicates that the SFRs of star-forming galaxies (SFGs) depend strongly on M_*_ (>99% confidence) with no dependence on R/R_200_ or projected local density at fixed mass. A merged sample of galaxies from the five best measured clusters shows <SFR>{prop.to}(R/R_200_)^1.1+/-0.3^ for galaxies with R/R_200_<=0.4. A decline in the fraction of SFGs toward the cluster center contributes most of this effect, but it is accompanied by a reduction in <SFR> for SFGs with R<=0.1R_200_. The increase in the fraction of SFGs toward larger R/R_200_ and the isolation of SFGs with reduced SFRs near the cluster center are consistent with the truncation of star formation by ram-pressure stripping, as is the tendency for more massive SFGs to have higher SFRs. We conclude that stripping is more likely than slower processes to drive the properties of SFGs with R<0.4R_200_ in clusters. We also find that galaxies near the cluster center are more massive than galaxies farther out in the cluster at ~3.5{sigma}, which suggests that dynamical relaxation significantly impacts the distribution of cluster galaxies as the clusters evolve.
2374. Multiwavelength study of nearby galaxy nuclei
ID:
ivo://CDS.VizieR/J/MNRAS/382/1552
Title:
Multiwavelength study of nearby galaxy nuclei
Short Name:
J/MNRAS/382/1552
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present optical and infrared broad-band images, radio maps, and optical spectroscopy for the nuclear region of a sample of nearby galaxies. The galaxies have been drawn from a complete volume-limited sample for which we have already presented X-ray imaging. We modelled the stellar component of the spectroscopic observations to determine the star formation history of our targets. Diagnostic diagrams were used to classify the emission-line spectra and determine the ionizing mechanism driving the nuclear regions. All those sources classified as active galactic nuclei present small Eddington ratios (~10^-3^-10^-6^), implying a very slow growth rate of their black holes. We finally investigate the relative numbers of active and normal nuclei as a function of host galaxy luminosity and find that the fraction of active galaxies slowly rises as a function of host absolute magnitude in the MB~-12 to -22 range.
2375. 16{mu}m imaging around the HDF-N
ID:
ivo://CDS.VizieR/J/ApJ/634/128
Title:
16{mu}m imaging around the HDF-N
Short Name:
J/ApJ/634/128
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a pilot study of 16{mu}m imaging within the GOODS northern field. Observations were obtained using the "peak-up" imaging capability of the Spitzer IRS. We survey 35arcmin^2^ to an average 3{sigma} depth of 0.075mJy and detect 149 sources.
2376. 500{mu}m-risers sources
ID:
ivo://CDS.VizieR/J/A+A/614/A33
Title:
500{mu}m-risers sources
Short Name:
J/A+A/614/A33
Date:
21 Oct 2021
Publisher:
CDS
Description:
Context. Over the last decade a large number of dusty star-forming galaxies has been discovered up to redshift z=2-3 and recent studies have attempted to push the highly confused Herschel SPIRE surveys beyond that distance. To search for z>=4 galaxies they often consider the sources with fluxes rising from 250{mu}m to 500{mu}m (so-called "500{mu}m-risers"). Herschel surveys offer a unique opportunity to efficiently select a large number of these rare objects, and thus gain insight into the prodigious star-forming activity that takes place in the very distant Universe. Aims. We aim to implement a novel method to obtain a statistical sample of 500{mu}m-risers and fully evaluate our selection inspecting different models of galaxy evolution. Methods. We consider one of the largest and deepest Herschel surveys, the Herschel Virgo Cluster Survey. We develop a novel selection algorithm which links the source extraction and spectral energy distribution fitting. To fully quantify selection biases we make end-to-end simulations including clustering and lensing. Results. We select 133 500{mu}m-risers over 55deg^2^, imposing the criteria: S_500_>S_350_>S_250_, S_250_>13.2mJy and S_500_>30mJy. Differential number counts are in fairly good agreement with models, displaying a better match than other existing samples. The estimated fraction of strongly lensed sources is 24_+6_^-5^% based on models.Conclusions. We present the faintest sample of 500{mu}m-risers down to S_250_=13.2mJy. We show that noise and strong lensing have an important impact on measured counts and redshift distribution of selected sources. We estimate the flux-corrected star formation rate density at 4<z<5 with the 500{mu}m-risers and find it to be close to the total value measured in far-infrared. This indicates that colour selection is not a limiting effect to search for the most massive, dusty z>4 sources.
2377. 16{mu}m sources in the NOAO Bootes field
ID:
ivo://CDS.VizieR/J/ApJ/634/L1
Title:
16{mu}m sources in the NOAO Bootes field
Short Name:
J/ApJ/634/L1
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the 16{mu}m peak-up imager on the Infrared Spectrograph (IRS) on Spitzer, we present a serendipitous survey of 0.0392{deg}^2^ within the area of the NOAO Deep Wide-Field Survey in Bootes. Combining our results with the available Multiband Imaging Photometer for Spitzer (MIPS) 24{mu}m survey of this area, we produce a catalog of 150 16{mu}m sources brighter than 0.18mJy (3{sigma}) for which we derive measures or limits on the 16{mu}m/24{mu}m colors. Such colors are especially useful in determining redshifts for sources whose mid-infrared spectra contain strong emission or absorption features that characterize these colors as a function of redshift.
2378. MUSE Catalog of UV emission line measurement
ID:
ivo://CDS.VizieR/J/A+A/654/A80
Title:
MUSE Catalog of UV emission line measurement
Short Name:
J/A+A/654/A80
Date:
02 Feb 2022 10:08:10
Publisher:
CDS
Description:
Rest-frame ultraviolet (UV) emission lines probe electron densities, gas-phase abundances, metallicities, and ionization parameters of the emitting star-forming galaxies and their environments. The strongest main UV emission line, Ly{alpha}, has been instrumental in advancing the general knowledge of galaxy formation in the early universe. However, observing Ly{alpha} emission becomes increasingly challenging at z>~6 when the neutral hydrogen fraction of the circumgalactic and intergalactic media increases. Secondary weaker UV emission lines provide important alternative methods for studying galaxy properties at high redshift. We present a large sample of rest-frame UV emission line sources at intermediate redshift for calibrating and exploring the connection between secondary UV lines and the emitting galaxies' physical properties and their Ly{alpha} emission. The sample of 2052 emission line sources with 1.5<z<6.4 was collected from integral field data from the MUSE-Wide and MUSE-Deep surveys taken as part of Guaranteed Time Observations. The objects were selected through untargeted source detection (i.e., no preselection of sources as in dedicated spectroscopic campaigns) in the three-dimensional MUSE data cubes. We searched optimally extracted one-dimensional spectra of the full sample for UV emission features via emission line template matching, resulting in a sample of more than 100 rest-frame UV emission line detections. We show that the detection efficiency of (non-Ly{alpha}) UV emission lines increases with survey depth, and that the emission line strength of HeII {lambda}1640AA, [OIII] {lambda}1661 + OIII] {lambda}1666, and [SiIII] {lambda}1883 + SiIII] {lambda}1892 correlate with the strength of [CIII] {lambda}1907 + CIII] {lambda}1909. The rest-frame equivalent width (EW0 ) of [CIII] {lambda}1907+CIII] {lambda}1909 is found to be roughly 0.22+/-0.18 of EW0 (Ly{alpha}). We measured the velocity offsets of resonant emission lines with respect to systemic tracers. For CIV {lambda}1548 + CIV {lambda}1551 we find that {DELTA}v_CIV_<~250km/s, whereas {nu}v_Ly{alpha}_ falls in the range of 250-500km/s which is in agreement with previous results from the literature. The electron density ne measured from [SiIII] {lambda}1883 + SiIII] {lambda}1892 and [CIII] {lambda}1907 + CIII] {lambda}1909 line flux ratios is generally <10^5^cm^-3^ and the gas-phase abundance is below solar at 12+log10(O/H)~=8. Lastly, we used "PhotoIonization Model Probability Density Functions" to infer physical parameters of the full sample and individual systems based on photoionization model parameter grids and observational constraints from our UV emission line searches. This reveals that the UV line emitters generally have ionization parameter log10(U) ~= -2.5 and metal mass fractions that scatter around Z~=10-2, that is Z~=0.66Z_{sun}_. Value-added catalogs of the full sample of MUSE objects studied in this work (this catalog) and a collection of UV line emitters from the literature are provided with this paper.
2379. MUSE combined data cubes for NGC 3311
ID:
ivo://CDS.VizieR/J/A+A/609/A78
Title:
MUSE combined data cubes for NGC 3311
Short Name:
J/A+A/609/A78
Date:
21 Oct 2021
Publisher:
CDS
Description:
Early-type galaxies (ETGs) show a strong size evolution with redshift. This evolution is explained by fast "in-situ" star formation at high-z followed by a late mass assembly mostly driven by minor mergers that deposit stars primarily in the outer halo. Aims: We aim to identify the main structural components of the Hydra I cD galaxy NGC 3311 to investigate the connection between the central galaxy and the surrounding stellar halo. We produce maps of the line-of-sight velocity distribution (LOSVD) moments from a mosaic of MUSE pointings covering NGC 3311 out to 25kpc. Combining deep photometric and spectroscopic data, we model the LOSVD maps using a finite mixture distribution, including four non-concentric components that are nearly isothermal spheroids, with different line-of-sight systemic velocities V, velocity dispersions sigma, and small (constant) values of the higher order Gauss-Hermite moments h_3_ and h_4_. The kinemetry analysis indicates that NGC 3311 is classified as a slow rotator, although the galaxy shows a line-of-sight velocity gradient along the photometric major axis. The comparison of the correlations between h_3_ and h_4_ with V{sigma} with simulated galaxies indicates that NGC 3311 assembled mainly through dry mergers. The sigma profile rises to approximately 400$ km/s at 20kpc, a significant fraction (0.55) of the Hydra I cluster velocity dispersion, indicating that stars there were stripped from progenitors orbiting in the cluster core. The finite mixture distribution modeling supports three inner components related to the central galaxy and a fourth component with large effective radius (51kpc) and velocity dispersion (327km/s) consistent with a cD envelope. We find that the cD envelope is offset from the center of NGC 3311 both spatially (8.6kpc) and in velocity ({delta}V=204km/s), but coincides with the cluster core X-ray isophotes and the mean velocity of core galaxies. Also, the envelope contributes to the broad wings of the LOSVD measured by large h_4 values within 10 kpc. The cD envelope of NGC 3311 is dynamically associated with the cluster core, which in Hydra I is in addition displaced from the cluster center, presumably due to a recent subcluster merger.
2380. MUSE datacube of He 2-10
ID:
ivo://CDS.VizieR/J/A+A/604/A101
Title:
MUSE datacube of He 2-10
Short Name:
J/A+A/604/A101
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the physical and dynamical properties of the ionized gas in the prototypical HII galaxy Henize 2-10 using MUSE integral field spectroscopy. The large-scale dynamics are dominated by extended outflowing bubbles that are probably the result of massive gas ejection from the central star forming regions. We derived a mass outflow rate dM_out_/dt~0.30M_{sun}_/yr, corresponding to mass loading factor {eta}~0.4, in the range of similar measurements in local LIRGs. Such a massive outflow has a total kinetic energy that is sustainable by the stellar winds and supernova remnants expected in the galaxy. We studied the dust extinction, electron density, and ionization conditions all across the galaxy with a classical emission line diagnostic, confirming the extreme nature of the highly star forming knots in the core of the galaxy, which show high density and high ionization parameters. We measured the gas-phase metallicity in the galaxy, taking the strong variation of the ionization parameter into account, and found that the external parts of the galaxy have abundances as low as 12+log(O/H)~8.3, while the central star forming knots are highly enriched with super solar metallicity. We found no sign of AGN ionization in the galaxy, despite the recent claim of the presence of a supermassive active black hole in the core of He 2-10. We therefore reanalyzed the X-ray data that were used to propose the presence of the AGN, but we concluded that the observed X-ray emission can be better explained with sources of a different nature, such as a supernova remnant.