- ID:
- ivo://CDS.VizieR/J/ApJ/455/60
- Title:
- CFRS II: 0000-00 and 1000+25 fields
- Short Name:
- J/ApJ/455/60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper describes the methods used to obtain the spectroscopic data and construct redshift catalogs for the Canada-France Deep Redshift Survey (CFRS). The full data set consists of more than 1000 spectra, of objects with 17.5=<I_AB_=<22.5, obtained from deep multislit data with the MARLIN and MOS-SIS spectrographs at the Canada-France-Hawaii Telescope (CFHT). The final spectroscopic catalog contains 200 stars, 591 galaxies with secure redshifts in the range 0=<z=<1.3, six QSOs, and 146 objects with very uncertain or unknown redshifts, leading to an overall success rate of identification of 85%. In addition, 67 objects affected by observational problems have been placed in a supplemental list. We describe here the instrumental setup and the observing procedures used to gather this large data set efficiently. New optimal ways of packing spectra on the detector to increase significantly the multiplexing gain offered by multislit spectroscopy are described. Dedicated data reduction procedures have been developed under the IRAF environment to allow for fast and accurate processing. Very strict procedures have been followed to establish a reliable list of final spectroscopic measurements. Fully independent processing of the data has been carried out by three members of the team for each data set associated with a multislit mask, and final redshifts were assigned only after the careful comparison of the three independent measurements. A confidence class scheme was established. We strongly emphasize the benefits of such procedures. Finally, we present the spectroscopic data obtained for 303 objects in the 0000-00 and 1000+25 fields. The success rate in spectroscopic identification is 83% for the 0000-00 field and 84% for the 1000+25 field.
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- ID:
- ivo://CDS.VizieR/J/ApJ/455/75
- Title:
- CFRS III: 1415+52 and 2215+00 fields
- Short Name:
- J/ApJ/455/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is one of a series describing the Canada-France Redshift Survey (CFRS). It is shown how the shape of the continuum around the emission line can be used to distinguish between [O II]{lambda}3727 at z>0.76 and H{alpha} at low redshift in spectra for which only a single isolated emission line is visible. Based on this, [O II]{lambda}3727 is most likely to be the emission line in most of the single emission-line galaxies in the CFRS. The statistics of the repeated observations are analyzed to derive an empirical calibration of the reliability of the spectroscopic identifications in the CFRS in order to determine how often additional observations could lead to the identification of an initially unidentified object and to provide an estimate of the internal velocity accuracy. Finally, the results of spectroscopic observations of 413 objects in the 1415+52 and 2215+00 CFRS survey fields are presented.
- ID:
- ivo://CDS.VizieR/J/ApJ/455/88
- Title:
- CFRS IV: 0300+00 field
- Short Name:
- J/ApJ/455/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Possible surface brightness selection effects in the redshift catalogs of the Canada-France Redshift Survey are investigated through comparisons of subsamples of the data. Our analyses demonstrate that the securing of redshifts is independent of possible biases arising from surface brightness effects and/or differing galaxy morphologies and orientations. The unusual geometry of the mask designs for our spectroscopic observations also do not produce any significant bias. There is, however, a bias at the highest and lowest redshifts, especially for absorption-line galaxies at z>1 and z<0.2, due to the adopted spectral range (4250-8500A). Apart from the latter, we conclude that our sample of identified galaxies is an unbiased subsample of the original photometric catalog and is essentially limited by I-band flux density (17.5<I_AB_<22.5). Finally, spectroscopic data for the remaining CFRS field is presented. Data for 272 objects in the 0300+0000 field are given.
- ID:
- ivo://CDS.VizieR/J/ApJ/464/79
- Title:
- CFRS XI: High-redshift field galaxies morphology
- Short Name:
- J/ApJ/464/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 143 galaxies with secure redshifts (Z_median_=0.62) from the 1415+52 field of the Canada-France Redshift Survey have been imaged with median seeing of 0.67" (FWHM). Structural parameters have been derived by fitting multicomponent models and the results confirm two phenomena seen in a smaller sample of galaxies imaged with the Hubble Space Telescope. First, 11+/-3% of the galaxies lie off the normal locus of color versus bulge fraction B/T. This class of objects ("blue nucleated galaxies," or BNGs) was identified using HST observations (Schade et al. 1995ApJ...451L...1S, hereafter CFRS IX), and it was shown that they are associated with peculiar/asymmetric structure and merger/interactions. The observed frequency of BNGs in this sample is 14+/-4% 0.5<z<1.2 and 6^+6^_-3_% at 0.2<z<0.5, but the true frequency is likely to be a factor ~2 higher after corrections are made for the effect of asymmetric/peculiar structures. Galaxy disks at 0.5<z<1.1 are found to have a mean rest-frame, inclination-corrected central surface brightness of {mu}_AB_(B)=19.8+/-0.1mag/arcsec^2^, ~1.6mag brighter than the Freeman (1970ApJ...160..811F) value. At low redshift (0.2<z<0.5) the mean surface brightness [{mu}_AB_(B)=21.3+/-0.25] is consistent with the Freeman value. These results are consistent with the HST observations. With larger numbers of galaxies and therefore more statistical weight they demonstrate the capabilities, and limits, of ground-based work in the study of galaxy morphology at high redshift.
- ID:
- ivo://CDS.VizieR/J/ApJ/481/49
- Title:
- CFRS XIV. Field galaxies up to z=1
- Short Name:
- J/ApJ/481/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spectral properties of more than 400 Canada-France Redshift Survey (CFRS) galaxies and their changes over the redshift interval 0<=z<=1.3 are investigated. Emission-line intensities and equivalent widths for accessible lines have been measured, as well as continuum color indices based on 200{AA} wide spectral regions.
- ID:
- ivo://CDS.VizieR/J/ApJS/233/20
- Title:
- CGM-MASS. II. New XMM data for 6 spirals
- Short Name:
- J/ApJS/233/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of the XMM-Newton data of the Circum-Galactic Medium of MASsive Spirals (CGM-MASS) sample of six extremely massive spiral galaxies in the local universe. All the CGM-MASS galaxies have diffuse X-ray emission from hot gas detected above the background extending ~(30-100)kpc from the galactic center. This doubles the existing detection of such extended hot CGM around massive spiral galaxies. The radial soft X-ray intensity profile of hot gas can be fitted with a {beta}-function, with the slope typically in the range of {beta}=0.35-0.55. This range, as well as those {beta} values measured for other massive spiral galaxies, including the Milky Way (MW), are in general consistent with X-ray luminous elliptical galaxies of similar hot gas luminosity and temperature, and with those predicted from a hydrostatic- isothermal gaseous halo. Hot gas in such a massive spiral galaxy tends to have temperature comparable to its virial value, indicating the importance of gravitational heating. This is in contrast to lower mass galaxies, where hot gas temperature tends to be systematically higher than the virial one. The ratio of the radiative cooling to free fall timescales of hot gas is much larger than the critical value of ~10 throughout the entire halos of all the CGM-MASS galaxies, indicating the inefficiency of gas cooling and precipitation in the CGM. The hot CGM in these massive spiral galaxies is thus most likely in a hydrostatic state, with the feedback material mixed with the CGM, instead of escaping out of the halo or falling back to the disk. We also homogenize and compare the halo X-ray luminosity measured for the CGM-MASS galaxies and other galaxy samples and discuss the "missing" galactic feedback detected in these massive spiral galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/845/87
- Title:
- CGS. V. Statistical study of bars and buckled bars
- Short Name:
- J/ApJ/845/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Simulations have shown that bars are subject to a vertical buckling instability that transforms thin bars into boxy or peanut-shaped structures, but the physical conditions necessary for buckling to occur are not fully understood. We use the large sample of local disk galaxies in the Carnegie-Irvine Galaxy Survey to examine the incidence of bars and buckled bars across the Hubble sequence. Depending on the disk inclination angle (i), a buckled bar reveals itself as either a boxy/peanut-shaped bulge (at high i) or as a barlens structure (at low i). We visually identify bars, boxy/peanut-shaped bulges, and barlenses, and examine the dependence of bar and buckled bar fractions on host galaxy properties, including Hubble type, stellar mass, color, and gas mass fraction. We find that the barred and unbarred disks show similar distributions in these physical parameters. The bar fraction is higher (70%-80%) in late-type disks with low stellar mass (M*<10^10.5^M_{sun}_) and high gas mass ratio. In contrast, the buckled bar fraction increases to 80% toward massive and early-type disks (M*>10^10.5^M_{sun}_), and decreases with higher gas mass ratio. These results suggest that bars are more difficult to grow in massive disks that are dynamically hotter than low-mass disks. However, once a bar forms, it can easily buckle in the massive disks, where a deeper potential can sustain the vertical resonant orbits. We also find a probable buckling bar candidate (ESO506-G004) that could provide further clues to understand the timescale of the buckling process.
- ID:
- ivo://CDS.VizieR/J/ApJS/192/10
- Title:
- Chandra ACIS survey in 383 nearby galaxies. I.
- Short Name:
- J/ApJS/192/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- By 2007 December 14, 383 galaxies within 40Mpc with isophotal major axis above 1arcmin had been observed by 626 public Chandra/ACIS observations, most of which were for the first time analyzed by this survey to study the X-ray point sources. Uniform data analysis procedures are applied to the 626 ACIS observations and lead to the detection of 28099 point sources, which belong to 17599 independent sources. These include 8700 sources observed twice or more and 1000 sources observed 10 times or more, providing us a wealth of data to study the long-term variability of these X-ray sources. Cross-correlation of these sources with galaxy isophotes led to 8519 sources within the D_25_ isophotes of 351 galaxies, 3305 sources between the D_25_ and 2D_25_ isophotes of 309 galaxies, and additionally 5735 sources outside 2D_25_ isophotes of galaxies. This survey has produced a uniform catalog, by far the largest, of 11824 X-ray point sources within 2D_25_ isophotes of 380 galaxies. Contamination analysis using the log N-log S relation shows that 74% of sources within 2D_25_ isophotes above 10^39^erg/s, 71% of sources above 10^38^erg/s, 63% of sources above 10^37^erg/s, and 56% of all sources are truly associated with galaxies. Meticulous efforts have identified 234 X-ray sources with galactic nuclei of nearby galaxies. This archival survey leads to 300 ultraluminous X-ray sources (ULXs) with L_X_(0.3-8keV)>=2x10^39^erg/s within D_25_ isophotes, 179 ULXs between D_25_ and 2D_25_ isophotes, and a total of 479 ULXs within 188 host galaxies, with about 324 ULXs truly associated with host galaxies based on the contamination analysis.
- ID:
- ivo://CDS.VizieR/J/ApJ/829/20
- Title:
- Chandra ACIS survey in nearby galaxies. II
- Short Name:
- J/ApJ/829/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on the recently completed Chandra/ACIS survey of X-ray point sources in nearby galaxies, we study the X-ray luminosity functions (XLFs) for X-ray point sources in different types of galaxies and the statistical properties of ultraluminous X-ray sources (ULXs). Uniform procedures are developed to compute the detection threshold, to estimate the foreground/background contamination, and to calculate the XLFs for individual galaxies and groups of galaxies, resulting in an XLF library of 343 galaxies of different types. With the large number of surveyed galaxies, we have studied the XLFs and ULX properties across different host galaxy types, and confirm with good statistics that the XLF slope flattens from lenticular ({alpha}{\sim}1.50{\pm}0.07) to elliptical ({\sim}1.21{\pm}0.02), to spirals ({\sim}0.80{\pm}0.02), to peculiars ({\sim}0.55{\pm}0.30), and to irregulars ({\sim}0.26{\pm}0.10). The XLF break dividing the neutron star and black hole binaries is also confirmed, albeit at quite different break luminosities for different types of galaxies. A radial dependency is found for ellipticals, with a flatter XLF slope for sources located between D_25_ and 2D_25_, suggesting the XLF slopes in the outer region of early-type galaxies are dominated by low-mass X-ray binaries in globular clusters. This study shows that the ULX rate in early-type galaxies is 0.24{\pm}0.05 ULXs per surveyed galaxy, on a 5{sigma} confidence level. The XLF for ULXs in late-type galaxies extends smoothly until it drops abruptly around 4x10^40^erg/s, and this break may suggest a mild boundary between the stellar black hole population possibly including 30M{\sun} black holes with super-Eddington radiation and intermediate mass black holes.
- ID:
- ivo://CDS.VizieR/J/ApJ/728/27
- Title:
- Chandra and AAOmega observations of Abell 2744
- Short Name:
- J/ApJ/728/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New Chandra X-ray data and extensive optical spectroscopy, obtained with AAOmega on the 3.9m Anglo-Australian Telescope, are used to study the complex merger taking place in the galaxy cluster Abell 2744. Combining our spectra with data from the literature provides a catalog of 1237 redshifts for extragalactic objects lying within 15' of the cluster center. From these, we confirm 343 cluster members projected within 3Mpc of the cluster center. Combining positions and velocities, we identify two major substructures, corresponding to the remnants of two major subclusters. The new data are consistent with a post-core-passage, major merger taking place along an axis that is tilted well out of the plane of the sky, together with an interloping minor merger. Supporting this interpretation, the new X-ray data reveal enriched, low entropy gas from the core of the approaching, major subcluster, lying ~2' north of the cluster center, and a shock front to the southeast of the previously known bright, compact core associated with the receding subcluster. The X-ray morphology of the compact core is consistent with a Bullet-like cluster viewed from within ~45{deg} of the merger axis. An X-ray peak ~3' northwest of the cluster center, with an associated cold front to the northeast and a trail of low entropy gas to the south, is interpreted as the remnant of an interloping minor merger taking place roughly in the plane of the sky. We infer approximate paths for the three merging components.