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- ID:
- ivo://CDS.VizieR/J/MNRAS/383/1513
- Title:
- 2MASS, SDSS and FIRST fluxes of QSOs
- Short Name:
- J/MNRAS/383/1513
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Starting from a sample of Sloan Digital Sky Survey quasars appearing also in the Two-Micron All-Sky Survey, we study the continuum properties of ~1000 objects observed in eight bands, from near-infrared to ultraviolet. We construct the mean spectral energy distribution (SED) and compare and contrast the continua of radio-loud and radio-quiet quasar (RLQ and RQQ, respectively) objects. The SEDs of the two populations are significantly different, in the sense that RLQs are redder with power-law spectral indices <alpha_RLQ_>=0.55+/-0.04 and <alpha_RQQ_>=0.31+/-0.01 in the spectral range between 10^14.5^ and 10^15.35^Hz. This difference is discussed in terms of different extinctions, different disc temperatures, or slopes of the non-thermal component.
- ID:
- ivo://CDS.VizieR/J/PASJ/63/S677
- Title:
- MAXI/GSC catalog in high Galactic-latitude sky
- Short Name:
- J/PASJ/63/S677
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first unbiased source catalog of the Monitor of All-sky X-ray Image (MAXI) mission at high Galactic latitudes (|b|>10{deg}), produced from the first 7-month data (2009 September 1 to 2010 March 31) of the Gas Slit Camera in the 4-10keV band. We have developed an analysis procedure to detect faint sources from the MAXI data, utilizing a maximum likelihood image fitting method, where the image response, background, and detailed observational conditions are taken into account. The catalog consists of 143 X-ray sources above the 7{sigma} significance level with a limiting sensitivity of ~1.5x10^-11^erg/cm^2^/s (1.2mCrab) in the 4-10keV band. Among them, we have identified 38 Galactic/LMC/SMC objects, 48 galaxy clusters, 39 Seyfert galaxies, 12 blazars, and 1 galaxy. Four other sources are confused with multiple objects, and one remains unidentified. The logN-logS relation of extragalactic objects is in good agreement with the HEAO-1 A-2 result, although the list of the brightest AGNs in the entire sky has significantly changed since that produced 30yr ago.
- ID:
- ivo://CDS.VizieR/VII/165A
- Title:
- Measured Redshifts of Abell Clusters of Galaxies
- Short Name:
- VII/165A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 'ACO' catalog (Abell, Corwin and Olowin 1989; Cat. VII/110) that contains 4076 rich (A-) clusters of galaxies and 1174 supplementary (S-) clusters was used to compile this catalog. In the compilation, many papers containing galaxy redshifts were checked for positional coincidences of objects with Abell clusters (typically within one Abell radius). In a total of 1059 ACO clusters a redshift for one or more galaxies were found. These 1059 clusters (records) are sorted by the R.A. (B1950) of their centre. Each record consists of cluster name, cluster centre equatorial coordinates (B1950), Abell richness, distance, Bautz-Morgan class, the magnitude of the tenth-brightest cluster member, cluster measured redshift, the reference code, the Abell radius, and the decimal log of the ratio between measured and estimated redshift.
215. MegaZ-LRG catalogue
- ID:
- ivo://CDS.VizieR/J/MNRAS/375/68
- Title:
- MegaZ-LRG catalogue
- Short Name:
- J/MNRAS/375/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the construction of MegaZ-LRG, a photometric redshift catalogue of over one million luminous red galaxies (LRGs) in the redshift range 0.4<z<0.7 with limiting magnitude i<20. The catalogue is selected from the imaging data of the Sloan Digital Sky Survey (SDSS) Data Release 4. The 2dF-SDSS LRG and Quasar (2SLAQ) spectroscopic redshift catalogue of 13000 intermediate-redshift LRGs provides a photometric redshift training set, allowing use of ANNZ, a neural network-based photometric-redshift estimator. The rms photometric redshift accuracy obtained for an evaluation set selected from the 2SLAQ sample is z=0.049 averaged over all galaxies, and z=0.040 for a brighter subsample (i<19.0). The catalogue is expected to contain ~5 per cent stellar contamination. The ANNZ code is used to compute a refined star/galaxy probability based on a range of photometric parameters; this allows the contamination fraction to be reduced to 2 per cent with negligible loss of genuine galaxies. The MegaZ-LRG catalogue is publicly available on the World Wide Web from http://www.2slaq.info .
- ID:
- ivo://CDS.VizieR/J/MNRAS/464/3882
- Title:
- Mergers and galaxy-galaxy interactions
- Short Name:
- J/MNRAS/464/3882
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Wide-field Infrared Survey Explorer (WISE) and the Sloan Digital Sky Survey (SDSS) to confirm a connection between dust-obscured active galactic nuclei (AGNs) and galaxy merging. Using a new, volume-limited (z<=0.08) catalogue of visually selected major mergers and galaxy-galaxy interactions from the SDSS, with stellar masses above 2x10^10^M_{sun}_, we find that major mergers (interactions) are 5-17 (3-5) times more likely to have red [3.4]-[4.6] colours associated with dust-obscured or 'dusty' AGNs, compared to non-merging galaxies with similar masses. Using published fibre spectral diagnostics, we map the [3.4]-[4.6] versus [4.6]-[12] colours of different emission-line galaxies and find that one-quarter of Seyferts have colours indicative of a dusty AGN. We find that AGNs are five times more likely to be obscured when hosted by a merging galaxy, half of AGNs hosted by a merger are dusty, and we find no enhanced frequency of optical AGNs in merging over non-merging galaxies. We conclude that undetected AGNs missed at shorter wavelengths are at the heart of the ongoing AGN-merger connection debate. The vast majority of mergers hosting dusty AGNs are star forming and located at the centres of M_halo_<10^13^Mc1l_{sun}_ groups. Assuming plausibly short-duration dusty-AGN phases, we speculate that a large fraction of gas-rich mergers experience a brief obscured AGN phase, in agreement with the strong connection between central star formation and black hole growth seen in merger simulations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/392/1539
- Title:
- Metal absorption systems in pairs of QSOs
- Short Name:
- J/MNRAS/392/1539
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first large sample of metal absorption systems in pairs of QSOs with sightlines separated by about 1Mpc at z=2. We found 690 absorption systems in the spectra of 310 QSOs in 170 pairings. Most systems show CIV or MgII absorption.
- ID:
- ivo://CDS.VizieR/J/PASP/118/1077
- Title:
- Metal-strong damped Ly{alpha} systems
- Short Name:
- J/PASP/118/1077
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified a metal-strong [logN(Zn+)>=13.15 or logN(Si^+^)>=15.95] damped Ly{alpha} (MSDLA) population from an automated quasar (QSO) absorber search in the Sloan Digital Sky Survey (SDSS) Data Release 3 quasar sample and find that MSDLAs comprise >>5% of the entire DLA population with z_abs_>=2.2 found in QSO sight lines with r<19.5. We have also acquired 27 Keck ESI (Echellete Spectrograph and Imager) follow-up spectra of metal strong candidates in order to evaluate our automated technique and examine the MSDLA candidates at higher resolution.
- ID:
- ivo://CDS.VizieR/J/MNRAS/354/L25
- Title:
- MgII absorbers in SDSS QSOs
- Short Name:
- J/MNRAS/354/L25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the cross-correlation between 212 Mg II quasar absorption systems and ~20000 luminous red galaxies (LRGs) selected from the Sloan Digital Sky Survey Data Release 1 (Cat. <J/AJ/126/2579>) in the redshift range 0.4<=z<=0.8. The Mg II systems were selected to have {lambda}{lambda}2796 and 2803 rest-frame equivalent widths >=1.0{AA} and identifications confirmed by the Fe II {lambda}2600 or Mg I {lambda}2852 lines.
- ID:
- ivo://CDS.VizieR/VII/240
- Title:
- Millennium Galaxy Catalogue
- Short Name:
- VII/240
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Millennium Galaxy Catalogue (MGC) is a 37.5deg^2^, medium-deep, B-band imaging survey along the celestial equator, taken with the Wide Field Camera on the Isaac Newton Telescope. The survey region is contained within the regions of both the Two Degree Field Galaxy Redshift Survey (2dFGRS) and the Sloan Digital Sky Survey Early Data Release (SDSS-EDR). The survey has a uniform isophotal detection limit of 26mag.arcsec^-2^ and it provides a robust, well-defined catalogue of stars and galaxies in the range 16<=B_MGC_<24 mag. Here we describe the survey strategy, the photometric and astrometric calibration, source detection and analysis, and present the galaxy number counts that connect the bright and faint galaxy populations within a single survey. We argue that these counts represent the state of the art and use them to constrain the normalizations ({phi}*) of a number of recent estimates of the local galaxy luminosity function. We find that the 2dFGRS, SDSS Commissioning Data (CD), ESO Slice Project, Century Survey, Durham/UKST, Mt Stromlo/APM, SSRS2 and NOG luminosity functions require a revision of their published {phi}* values by factors of 1.05+/-0.05, 0.76+/-0.10, 1.02+/-0.22, 1.02+/-0.16, 1.16+/-0.28, 1.75+/-0.37, 1.40+/-0.26 and 1.01+/-0.39, respectively. After renormalizing the galaxy luminosity functions we find a mean local b_J_ luminosity density of 1.986+/-0.031x10^8^h L_{sun}_.Mpc^-3^
