- ID:
- ivo://CDS.VizieR/J/ApJS/119/159
- Title:
- Deep survey of HI-selected galaxies
- Short Name:
- J/ApJS/119/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a 21cm neutral hydrogen survey of approximately 55{deg}^2^ out to a redshift of cz=8340km/s, we have identified 75 extragalactic HI sources. These objects comprise a well-defined sample of extragalactic sources chosen by means that are independent of optical surface brightness selection effects. In this paper we describe the Arecibo survey procedures and HI data, follow-up VLA HI observations made of several unusual sources, and Kitt Peak B-, R-, and I-band photometry for nearly all of the galaxies. We have also gathered information for some of the optically detected galaxies within the same search volume.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/533/A91
- Title:
- Deep VI imaging in outer regions of M33
- Short Name:
- J/A+A/533/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Subaru/Suprime-Cam deep V and I imaging of seven fields in the outer regions of M33. Our aim is to search for stellar structures corresponding to extended HI clouds found in a recent 21-cm survey of the galaxy. Three fields probe a large HI complex to the southeastern (SE) side of the galaxy. An additional three fields cover the northwestern (NW) side of the galaxy along the HI warp. A final target field was chosen further north, at a projected distance of approximately 25kpc, to study part of the large stellar plume recently discovered around M33. We analyse the stellar population at R>10kpc by means of V, I colour magnitude diagrams reaching the red clump. We constrain the age and metallicity of the different stellar populations, search for density enhancements that correspond to the HI features, and investigate the radial surface distribution of the stars. We find evolved stellar populations in all fields out to 120' (~30kpc), while a diffuse population of young stars (~200Myr) is detected out to a galactocentric radius of 15kpc. The mean metallicity in the southern fields remains approximately constant at [M/H]=-0.7 beyond the edge of the optical disc, from 40' out to 80'. Along the northern fields probing the outer HI disc, we also find a metallicity of [M/H]=-0.7 between 35' and 70' from the centre, which decreases to [M/H]=-1.0 at larger angular radii out to 120'. In the northernmost field, outside the disc extent, the stellar population of the large stellar plume possibly related to a M33-M31 interaction is on average more metal-poor ([M/H]=-1.3) and older (>6Gyr). An exponential disc with a large scale-length (~7kpc) fits well the average distribution of stars detected in both the SE and NW regions from a galactocentric distance of 11kpc out to 30kpc. The stellar disc extends beyond the HI disc. The stellar distribution at large radii is disturbed and, although there is no clear correlation between the stellar substructures and the location of the HI clouds, this gives evidence of tidal interaction or accretion events.
- ID:
- ivo://CDS.VizieR/J/A+A/629/A18
- Title:
- Deep VI photometry of 15 dwarf galaxy candidates
- Short Name:
- J/A+A/629/A18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dwarf galaxy satellite systems are essential probes to test models of structure formation, making it necessary to establish a census of dwarf galaxies outside of our own Local Group. We present deep FORS2 VI band images from the ESO Very Large Telescope (VLT) for 15 dwarf galaxy candidates in the Centaurus group of galaxies. We confirm nine dwarfs to be members of Cen A by measuring their distances using a Bayesian approach to determine the tip of the red giant branch luminosity. We have also fit theoretical isochrones to measure their mean metallicities. The properties of the new dwarfs are similar to those in the Local Group in terms of their sizes, luminosities, and mean metallicities. Within our photometric precision, there is no evidence of a metallicity spread, but we do observe possible extended star formation in several galaxies, as evidenced by a population of asymptotic giant branch stars brighter than the red giant branch tip. The new dwarfs do not show any signs of tidal disruption. Together with the recently reported dwarf galaxies by the complementary PISCeS survey, we study the luminosity function and 3D structure of the group. By comparing the observed luminosity function to the high-resolution cosmological simulation IllustrisTNG, we find agreement within a 90% confidence interval.However, Cen A seems to be missing its brightest satellites and has an overabundance of the faintest dwarfs in comparison to its simulated analogs. In terms of the overall 3D distribution of the observed satellites, we find that the whole structure is flattened along the line-of-sight, with a root-mean-square (rms) height of 130kpc and an rms semi-major axis length of 330kpc. Future distance measurements of the remaining dwarf galaxy candidates are needed to complete the census of dwarf galaxies in the Centaurus group.
- ID:
- ivo://CDS.VizieR/J/A+A/570/A78
- Title:
- Deep VI photometry of Sgr dIrr
- Short Name:
- J/A+A/570/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric catalogue of the dwarf irregular galaxy Sagittarius. The catalogue is obtained from deep V and I band wide field photometry from VIMOS at VLT. Only sources having at least six independent magnitude estimates per filter were included in this catalogue. The average and the standard error of the mean of the independent measures obtained from the different images were adopted as the final values of the instrumental magnitude and of the uncertainty on the relative photometry. The instrumental v and i magnitudes were transformed into the Johnson-Kron-Cousins V,I photometric system using more than 70 bright stars (V<22.5) in common with the publicly available HST Wide Field and Planetary Camera 2 (WFPC2) photometry by Holtzman et al. (2006ApJS..166..534H). The instrumental coordinates were transformed into J2000 Equatorial coordinates with 2nd degree polynomials, using more than 1000 stars in common with the GSC2.2 catalog. Please see Section 2.2 for details.
- ID:
- ivo://CDS.VizieR/J/ApJ/836/137
- Title:
- Deep, wide-field g,i imaging of And XXXI
- Short Name:
- J/ApJ/836/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from WIYN pODI imaging of Lacerta I (And XXXI), a satellite dwarf galaxy discovered in the outskirts of the Andromeda galaxy (M31) in Pan-STARRS1 survey data. Our deep, wide-field g,i photometry reaches ~3mag fainter than the photometry in the Pan-STARRS1 discovery paper and allows us to trace the stellar population of Lac I beyond two half-light radii from the galaxy center. We measure a Tip of the Red Giant Branch distance for Lac I of (m-M)_0_=24.44+/-0.11mag (773+/-40kpc, or 264+/-6kpc from M31), which is consistent with the Pan-STARRS1 distance. We use a maximum-likelihood technique to derive structural properties for the galaxy, and find a half-light radius (r_h_) of 3.24+/-0.21' (728+/-47pc), ellipticity ({epsilon}) of 0.44+/-0.03, total magnitude M_V_=-11.4+/-0.3, and central surface brightness {mu}_V,0_=24.8+/-0.3mag/arcsec^2^. We find no H I emission in archival data and set a limit on Lac I's neutral gas mass-to-light ratio of M_HI_/L_V_<0.06M_{sun}_/L_{sun}_, confirming Lac I as a gas-poor dwarf spheroidal galaxy. Photometric metallicities derived from Red Giant Branch stars within 2 r_h_ yield a median [Fe/H] of -1.68+/-0.03, which is more metal-rich than the spectroscopically derived value from Martin+ (2014ApJ...793L..14M). Combining our measured magnitude with this higher metallicity estimate places Lac I closer to its expected position on the luminosity-metallicity relation for dwarf galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/218/9
- Title:
- Deep XMM-Newton survey of M33
- Short Name:
- J/ApJS/218/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained a deep 8 field XMM-Newton mosaic of M33 covering the galaxy out to the D_25_ isophote and beyond to a limiting 0.2-4.5keV unabsorbed flux of 5x10^-16^erg/cm2/s (L>4x10^34^erg/s at the distance of M33). These data allow complete coverage of the galaxy with high sensitivity to soft sources such as diffuse hot gas and supernova remnants (SNRs). Here, we describe the methods we used to identify and characterize 1296 point sources in the 8 fields. We compare our resulting source catalog to the literature, note variable sources, construct hardness ratios, classify soft sources, analyze the source density profile, and measure the X-ray luminosity function (XLF). As a result of the large effective area of XMM-Newton below 1keV, the survey contains many new soft X-ray sources. The radial source density profile and XLF for the sources suggest that only ~15% of the 391 bright sources with L>3.6x10^35^erg/s are likely to be associated with M33, and more than a third of these are known SNRs. The log(N)-log(S) distribution, when corrected for background contamination, is a relatively flat power law with a differential index of 1.5, which suggests that many of the other M33 sources may be high-mass X-ray binaries. Finally, we note the discovery of an interesting new transient X-ray source, which we are unable to classify.
- ID:
- ivo://CDS.VizieR/J/A+A/534/A55
- Title:
- Deep XMM-Newton Survey of M31
- Short Name:
- J/A+A/534/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The largest Local Group spiral galaxy, M31, has been completely imaged for the first time, obtaining a luminosity lower limit about 10^35^erg/s in the 0.2-4.5keV band. Our XMM-Newton EPIC survey combines archival observations along the major axis, from June 2000 to July 2004, with observations taken between June 2006 and February 2008 that cover the remainder of the D_25_ ellipse. The main goal of the paper is to study X-ray source populations of M31. An X-ray catalogue of 1897(*) sources was created with 914 detected for the first time. Source classification and identification were based on X-ray hardness ratios, spatial extent of the sources, and cross correlation with catalogues in the X-ray, optical, infrared and radio wavelengths. We also analysed the long-term variability of the X-ray sources and this variability allows us to distinguish between X-ray binaries and active galactic nuclei (AGN). Furthermore, supernova remnant classifications of previous studies that did not use long-term variability as a classification criterion could be validated. Including previous Chandra and ROSAT observations in the long-term variability study allowed us to detect additional transient or at least highly variable sources, which are good candidate X-ray binaries. (*) the final catalog of table5 icludes 1948 sources.
- ID:
- ivo://CDS.VizieR/J/A+A/438/507
- Title:
- Degree of lopsidedness for galaxies
- Short Name:
- J/A+A/438/507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We quantify the degree of lopsidedness for a sample of 149 galaxies observed in the near-infrared from the Ohio State University Bright Galaxy Survey (OSUBGS, Eskridge et al. 2002, Cat. <J/ApJS/143/73>) sample, and try to explain the physical origin of the observed disk lopsidedness. We confirm previous studies, but for a larger sample, that a large fraction of galaxies have significant lopsidedness in their stellar disks, measured as the Fourier amplitude of the m=1 component normalised to the average or m=0 component in the surface density. Late-type galaxies are found to be more lopsided, while the presence of m=2 spiral arms and bars is correlated with disk lopsidedness. We also show that the m=1 amplitude is uncorrelated with the presence of companions. Numerical simulations were carried out to study the generation of m=1 via different processes: galaxy tidal encounters, galaxy mergers, and external gas accretion with subsequent star formation. These simulations show that galaxy interactions and mergers can trigger strong lopsidedness, but do not explain several independent statistical properties of observed galaxies. To explain all the observational results, it is required that a large fraction of lopsidedness results from cosmological accretion of gas on galactic disks, which can create strongly lopsided disks when this accretion is asymmetrical enough.
- ID:
- ivo://CDS.VizieR/J/ApJ/799/148
- Title:
- DEIMOS galaxy sample at z~0.7
- Short Name:
- J/ApJ/799/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Scaling relations between galaxy structures and dynamics have been studied extensively for early- and late-type galaxies, both in the local universe and at high redshifts. The abundant differences between the properties of disky and elliptical, or star-forming and quiescent, galaxies seem to be characteristic of the local universe; such clear distinctions begin to disintegrate as observations of massive galaxies probe higher redshifts. In this paper we investigate the existence of the mass fundamental plane of all massive galaxies ({sigma}>~100km/s). This work includes local galaxies (0.05<z<0.07) from the Sloan Digital Sky Survey, in addition to 31 star-forming and 72 quiescent massive galaxies at intermediate redshift (z~0.7) with absorption-line kinematics from deep Keck-DEIMOS spectra and structural parameters from Hubble Space Telescope imaging. In two-parameter scaling relations, star-forming and quiescent galaxies differ structurally and dynamically. However, we show that massive star-forming and quiescent galaxies lie on nearly the same mass fundamental plane, or the relationship between stellar mass surface density, stellar velocity dispersion, and effective radius. The scatter in this relation (measured about log{sigma}) is low: 0.072dex (0.055dex intrinsic) at z~0 and 0.10dex (0.08dex intrinsic) at z~0.7. This 3D surface is not unique: virial relations, with or without a dependence on luminosity profile shapes, can connect galaxy structures and stellar dynamics with similar scatter. This result builds on the recent finding that mass fundamental plane has been stable for early-type galaxies since z~2. As we now find that this also holds for star-forming galaxies to z~0.7, this implies that these scaling relations of galaxies will be minimally susceptible to progenitor biases owing to the evolving stellar populations, structures, and dynamics of galaxies through cosmic time.
- ID:
- ivo://CDS.VizieR/J/ApJ/858/77
- Title:
- DEIMOS 10K spectroscopic survey in COSMOS field
- Short Name:
- J/ApJ/858/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 10718 objects in the COSMOS field, observed through multi-slit spectroscopy with the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II telescope in the wavelength range ~5500-9800{AA}. The catalog contains 6617 objects with high-quality spectra (two or more spectral features), and 1798 objects with a single spectroscopic feature confirmed by the photometric redshift. For 2024 typically faint objects, we could not obtain reliable redshifts. The objects have been selected from a variety of input catalogs based on multi-wavelength observations in the field, and thus have a diverse selection function, which enables the study of the diversity in the galaxy population. The magnitude distribution of our objects is peaked at I_AB_~23 and K_AB_~21, with a secondary peak at K_AB_~24. We sample a broad redshift distribution in the range 0<z<6, with one peak at z~1, and another one around z~4. We have identified 13 redshift spikes at z>0.65 with chance probabilities <4x10^-4^, some of which are clearly related to protocluster structures of sizes >10Mpc. An object-to-object comparison with a multitude of other spectroscopic samples in the same field shows that our DEIMOS sample is among the best in terms of fraction of spectroscopic failures and relative redshift accuracy. We have determined the fraction of spectroscopic blends to about 0.8% in our sample. This is likely a lower limit and at any rate well below the most pessimistic expectations. Interestingly, we find evidence for strong lensing of Ly{alpha} background emitters within the slits of 12 of our target galaxies, increasing their apparent density by about a factor of 4.
