- ID:
- ivo://CDS.VizieR/J/ApJ/835/280
- Title:
- WISE MIR properties of galaxies in compact groups
- Short Name:
- J/ApJ/835/280
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the mid-infrared (MIR) properties of galaxies in compact groups and their environmental dependence using the Wide-field Infrared Survey Explorer (WISE) data. We use a volume-limited sample of 670 compact groups and their 2175 member galaxies with M_r_<-19.77 and 0.01<z<0.0741, drawn from Sohn+ (2016, J/ApJS/225/23), which were identified using a friends-of-friends algorithm. Among the 2175 galaxies, 1541 galaxies are detected at WISE 12um with a signal-to-noise ratio greater than 3. Among the 1541 galaxies, 433 AGN-host galaxies are identified by using both optical and MIR classification schemes. Using the remaining 1108 non-AGN galaxies, we find that the MIR [3.4]-[12] colors of compact group early-type galaxies are on average bluer than those of cluster early-type galaxies. When compact groups have both early- and late-type member galaxies, the MIR colors of the late-type members in those compact groups are bluer than the MIR colors of cluster late-type galaxies. As compact groups are located in denser regions, they tend to have larger early-type galaxy fractions and bluer MIR color galaxies. These trends are also seen for neighboring galaxies around compact groups. However, compact group member galaxies always have larger early-type galaxy fractions and bluer MIR colors than their neighboring galaxies. Our findings suggest that the properties of compact group galaxies depend on both internal and external environments of compact groups, and that galaxy evolution is faster in compact groups than in the central regions of clusters.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/255/10
- Title:
- WISE MIR variability in gamma-ray Seyfert 1 gal.
- Short Name:
- J/ApJS/255/10
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- Fermi-LAT's detection of {gamma}-rays from narrow-line Seyfert 1 galaxies (NLS1s) has received increasing attention. Understanding these {gamma}-NLS1s is of interest because they have some properties similar to blazars, which are known to show rapid and large-amplitude variability. Based on the largest sample of {gamma}-NLS1s (25 sources), we carried out a systematic search for rapid mid-infrared (MIR, 3.4 and 4.6{mu}m) variability using the multiepoch data of the Wide-field Infrared Survey Explorer (WISE). We also compared a few variability properties between {gamma}-NLS1s and {gamma}-ray blazars. Our main results are as follows. (1) Thirteen {gamma}-NLS1s showed significant (>3{sigma}) rapid variability in at least one of the two MIR bands. The MIR emission of these sources is dominated by the synchrotron emission of relativistic electrons in the jet. (2) The {gamma}-NLS1s with flat radio spectra are more variable than those not detected in {gamma}-rays. (3) The {gamma}-NLS1s tend to show smaller amplitude of variability as well as lower duty cycle relative to {gamma}-ray blazars. (4) The {gamma}-NLS1s tend to show a trend of bluer-when-brighter on both intraday and long timescales, similar to {gamma}-ray blazars. (5) The {gamma}-NLS1s that are more variable on long timescales have larger amplitudes of variability and higher duty cycles on intraday timescales. (6) In the majority of cases, the {gamma}-NLS1s fall in the WISE Gamma-ray Blazar Strip (WGS). However, we noted migrations outside of the WGS due to significant variability.
- ID:
- ivo://CDS.VizieR/J/ApJS/182/625
- Title:
- WIYN spectroscopy in the deep SWIRE field
- Short Name:
- J/ApJS/182/625
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of spectroscopy using HYDRA on the WIYN 3.5m telescope of objects in the deep SWIRE radio field. The goal of the project was to determine spectroscopic redshifts for as many of the brighter objects in the field as possible, especially those detected in the radio and at 24um. These redshifts are primarily being used in studies of galaxy evolution and the connection of that evolution to active galactic nuclei and star formation. Redshifts measured for 365 individual objects are reported. The redshifts range from 0.03 to 2.5, mostly with z<0.9. The sources were selected to be within the WIYN HYDRA field of approximately 30' in radius from the center of the SWIRE deep field, 10:46:00, +59:01:00 (J2000). Optical sources for spectroscopic observation were selected from an r-band image of the field. A priority list of spectroscopic targets was established in the following order: 20cm detections, 24m detections, galaxies with r<20 and the balance made up of fainter galaxies in the field. We provide a table listing the galaxy positions, measured redshift and error, and note any emission lines that were visible in the spectrum. In practice, almost all the galaxies with r<19 were observed including all of the radio sources and most of the 24um sources with r<20 and a sample of radio sources which had fainter optical counterparts on the r-band image.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/43
- Title:
- WWFI g'-band obs. of bright cluster galaxies
- Short Name:
- J/ApJS/247/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of 170 local (z<~0.08) galaxy clusters in the northern hemisphere have been obtained with the Wendelstein Telescope Wide Field Imager (WWFI). We correct for systematic effects such as point-spread function broadening, foreground star contamination, relative bias offsets, and charge persistence. Background inhomogeneities induced by scattered light are reduced down to {Delta}SB>31 g' mag/arcsec^2^ by large dithering and subtraction of night-sky flats. Residual background inhomogeneities brighter than SB_{sigma}_<27.6 g' mag/arcsec^2^ caused by galactic cirrus are detected in front of 23% of the clusters. However, the large field of view allows discrimination between accretion signatures and galactic cirrus. We detect accretion signatures in the form of tidal streams in 22%, shells in 9.4%, and multiple nuclei in 47% of the brightest cluster galaxies (BCGs) and find two BCGs in 7% of the clusters. We measure semimajor-axis surface brightness profiles of the BCGs and their surrounding intracluster light (ICL) down to a limiting surface brightness of SB=30 g' mag/arcsec^2^. The spatial resolution in the inner regions is increased by combining the WWFI light profiles with those that we measured from archival Hubble Space Telescope images or deconvolved WWFI images. We find that 71% of the BCG+ICL systems have surface brightness (SB) profiles that are well described by a single Sersic function, whereas 29% require a double Sersic function to obtain a good fit. We find that BCGs have scaling relations that differ markedly from those of normal ellipticals, likely due to their indistinguishable embedding in the ICL.
- ID:
- ivo://CDS.VizieR/J/ApJ/761/125
- Title:
- X and {gamma} spectral indexes of Fermi blazars
- Short Name:
- J/ApJ/761/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, a sample of 451 blazars (193 flat spectrum radio quasars (FSRQs), 258 BL Lacertae objects) with corresponding X-ray and Fermi {gamma}-ray data is compiled to investigate the correlation both between the X-ray spectral index and the {gamma}-ray spectral index and between the spectral index and the luminosity, and to compare the spectral indexes {alpha}_X_, {alpha}_{gamma}_, {alpha}_X{gamma}_, and {alpha}_{gamma}X{gamma}_ for different subclasses. We also investigated the correlation between the X-ray and the {gamma}-ray luminosity.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A39
- Title:
- X-ATLAS X-ray sources photometric redshifts
- Short Name:
- J/A+A/608/A39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric redshifts for 1,031 X-ray sources in the X-ATLAS field using the machine-learning technique TPZ. X-ATLAS covers 7.1 deg2 observed with XMM-Newton within the Science Demonstration Phase (SDP) of the H-ATLAS field, making it one of the largest contiguous areas of the sky with both XMM-Newton and Herschel coverage. All of the sources have available SDSS photometry, while 810 additionally have mid-IR and/or near-IR photometry. A spectroscopic sample of 5,157 sources primarily in the XMM/XXL field, but also from several X-ray surveys and the SDSS DR13 redshift catalogue, was used to train the algorithm. Our analysis reveals that the algorithm performs best when the sources are split, based on their optical morphology, into point-like and extended sources. Optical photometry alone is not enough to estimate accurate photometric redshifts, but the results greatly improve when at least mid-IR photometry is added in the training process. In particular, our measurements show that the estimated photometric redshifts for the X-ray sources of the training sample have a normalized absolute median deviation, nmadh0.06, and a percentage of outliers, {eta}=10-14%, depending upon whether the sources are extended or point like. Our final catalogue contains photometric redshifts for 933 out of the 1,031 X-ray sources with a median redshift of 0.9.
1597. xCOLD GASS catalog
- ID:
- ivo://CDS.VizieR/J/ApJS/233/22
- Title:
- xCOLD GASS catalog
- Short Name:
- J/ApJS/233/22
- Date:
- 02 Nov 2021 07:14:32
- Publisher:
- CDS
- Description:
- We introduce xCOLD GASS, a legacy survey providing a census of molecular gas in the local universe. Building on the original COLD GASS survey, we present here the full sample of 532 galaxies with CO (1-0) measurements from the IRAM 30m telescope. The sample is mass-selected in the redshift interval 0.01<z<0.05 from the Sloan Digital Sky Survey (SDSS) and therefore representative of the local galaxy population with M_*_>10^9^M_{sun}_. The CO (1-0) flux measurements are complemented by observations of the CO (2-1) line with both the IRAM 30 m and APEX telescopes, HI observations from Arecibo, and photometry from SDSS, WISE, and GALEX. Combining the IRAM and APEX data, we find that the ratio of CO (2-1) to CO (1-0) luminosity for integrated measurements is r_21_=0.79+/- 0.03, with no systematic variations across the sample. The CO (1-0) luminosity function is constructed and best fit with a Schechter function with parameters L_CO_^* ^=(7.77+/-2.11)x10^9^K.(km/s).pc^2^, {phi}^*^=(9.84+/-5.41)x10^-4^Mpc^-3^, and {alpha}=-1.19+/-0.05. With the sample now complete down to stellar masses of 10^9^M_{sun}_, we are able to extend our study of gas scaling relations and confirm that both molecular gas fractions (f_H2_) and depletion timescale (t_dep_(H2)) vary with specific star formation rate (or offset from the star formation main sequence) much more strongly than they depend on stellar mass. Comparing the xCOLD GASS results with outputs from hydrodynamic and semianalytic models, we highlight the constraining power of cold gas scaling relations on models of galaxy formation.
1598. XMM-COSMOS Type 1 AGNs
- ID:
- ivo://CDS.VizieR/J/A+A/512/A34
- Title:
- XMM-COSMOS Type 1 AGNs
- Short Name:
- J/A+A/512/A34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the X-ray to optical properties of a sample of 545 X-ray selected Type 1 AGN, from the XMM-COSMOS survey, over a wide range of redshifts (0.04<z<4.25) and X-ray luminosities (40.6<=LogL[2-10]keV<=45.3). About 60% of them are spectroscopically identified Type 1 AGN, while the others have a reliable photometric redshift and are classified as Type 1 AGN on the basis of their multi-band Spectral Energy Distributions. We discuss the relationship between UV and X-ray luminosity, as parameterized by the alpha_ox_ spectral slope, and its dependence on redshift and luminosity.
- ID:
- ivo://CDS.VizieR/J/PAZh/45/464
- Title:
- 3XMM-DR4 QSO candidates optical spectroscopy
- Short Name:
- J/PAZh/45/464
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the results of optical spectroscopy for 58 quasar candidates at photometric redshifts z>~3, 57 of which enter into the Khorunzhev et al. (2016, Cat. J/PAZh/42/313) catalog (K16). This is a catalog of quasar candidates and known type 1 quasars selected among the X-ray sources of the 3XMM-DR4 catalog of the XMM-Newton serendipitous survey. At first we have performed spectroscopy for a quasi-random sample of 19 candidates at the 1.6-m AZT-33IK telescope of the Sayan Solar Observatory and the 6-m BTA telescope of the Special Astrophysical Observatory (SAO RAS). Then we have continued the observation for 39 X-ray bright candidates that could be used for the X-ray luminosity function construction (see Khorunzhev et al. 2018AstL...44..500K). The spectra at AZT-33IK were taken with the new low- and medium-resolution ADAM spectrograph that was produced and installed on the telescope in 2015. One of the most distant (z=5.08) optically bright (i=21) quasars ever detected in X-ray surveys has been discovered.
- ID:
- ivo://CDS.VizieR/J/A+A/557/A81
- Title:
- XMM-LSS field X-ray sources classification
- Short Name:
- J/A+A/557/A81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The XMM-Large Scale Structure survey (XMM-LSS), covering an area of 11.1 sq. deg., contains more than 6000 X-ray point-like sources detected with XMM-Newton to a flux of 3x10^-15^erg/s/cm^2^ in the [0.5-2]keV band. The vast majority of these sources have optical (CFHTLS), infrared (SWIRE IRAC and MIPS), near-infrared (UKIDSS) and/or ultraviolet (GALEX) counterparts. We wish to investigate the environmental properties of the different types of the XMM-LSS X-ray sources by defining their environment using the i'-band CFHTLS W1 catalog of optical galaxies to a magnitude limit of 23.5mag. We have classified 4435 X-ray selected sources on the basis of their spectra, SEDs, and X-ray luminosity, and estimated their photometric redshifts, which have a 4-11 band photometry with an accuracy of sigma_dz_/(1+z_sp_)=0.076 with 22.6% outliers for i'<26mag. We estimated the local overdensities of 777 X-ray sources that have spectro-z or photo-z calculated by using more than seven bands (accuracy of sigma_dz_/(1+z_sp_)=0.061 with 13.8% outliers) within the volume-limited region defined by 0.1<z<0.85 and -23.5<M_i'_<-20. Although X-ray sources may be found in variety of environments, a high fraction (~55-60%), as verified by comparing with the random expectations, reside in overdense regions. The galaxy overdensities within which X-ray sources reside show a positive recent redshift evolution (at least for the range studied; z<0.85). We also find that X-ray selected galaxies, when compared to AGN, inhabit significantly higher galaxy overdensities, although their spatial extent appear to be smaller than that of AGN. Hard AGN (HR>-0.2) are located in more overdense regions than soft AGN (HR<-0.2), which is clearly seen in both redshift ranges, although it appears to be stronger in the higher redshift range (0.55<z<0.85). Furthermore, the galaxy overdensities (with {delta}>1.5) within which soft AGN are embedded appear to evolve more rapidly compared to the corresponding overdensities around hard AGN.
