- ID:
- ivo://CDS.VizieR/J/ApJ/813/77
- Title:
- Galaxy clusters: radio halos, relics and parameters
- Short Name:
- J/ApJ/813/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Diffuse radio emission in galaxy clusters is known to be related to cluster mass and cluster dynamical state. We collect the observed fluxes of radio halos, relics, and mini-halos for a sample of galaxy clusters from the literature, and calculate their radio powers. We then obtain the values of cluster mass or mass proxies from previous observations, and also obtain the various dynamical parameters of these galaxy clusters from optical and X-ray data. The radio powers of relics, halos, and mini-halos are correlated with the cluster masses or mass proxies, as found by previous authors, while the correlations concerning giant radio halos are in general the strongest. We found that the inclusion of dynamical parameters as the third dimension can significantly reduce the data scatter for the scaling relations, especially for radio halos. We therefore conclude that the substructures in X-ray images of galaxy clusters and the irregular distributions of optical brightness of member galaxies can be used to quantitatively characterize the shock waves and turbulence in the intracluster medium responsible for re-accelerating particles to generate the observed diffuse radio emission. The power of radio halos and relics is correlated with cluster mass proxies and dynamical parameters in the form of a fundamental plane.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/465/2616
- Title:
- Galaxy cluster's rotation
- Short Name:
- J/MNRAS/465/2616
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the possible rotation of cluster galaxies, developing, testing, and applying a novel algorithm which identifies rotation, if such does exist, as well as its rotational centre, its axis orientation, rotational velocity amplitude, and, finally, the clockwise or counterclockwise direction of rotation on the plane of the sky. To validate our algorithms we construct realistic Monte Carlo mock rotating clusters and confirm that our method provides robust indications of rotation. We then apply our methodology on a sample of Abell clusters with z<=0.1 with member galaxies selected from the Sloan Digital Sky Survey DR10 spectroscopic data base. After excluding a number of substructured clusters, which could provide erroneous indications of rotation, and taking into account the expected fraction of misidentified coherent substructure velocities for rotation, provided by our Monte Carlo simulation analysis, we find that ~23 per cent of our clusters are rotating under a set of strict criteria. Loosening the strictness of the criteria, on the expense of introducing spurious rotation indications, we find this fraction increasing to ~28 per cent. We correlate our rotation indicators with the cluster dynamical state, provided either by their Bautz-Morgan type or by their X-ray isophotal shape and find for those clusters showing rotation within 1.5h^-1^_70_ Mpc that the significance of their rotation is related to the dynamically younger phases of cluster formation but after the initial anisotropic accretion and merging has been completed. Finally, finding rotational modes in galaxy clusters could lead to the necessity of correcting the dynamical cluster mass calculations.
- ID:
- ivo://CDS.VizieR/J/A+A/338/813
- Title:
- Galaxy clusters {sigma}-T relationship
- Short Name:
- J/A+A/338/813
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is a sample of 149 galaxy clusters for which both the X-ray determined temperature T of the intracluster gas and the optical measured velocity dispersion {sigma} of the cluster galaxies have been available.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A83
- Title:
- Galaxy cluster strong lensing cosmography
- Short Name:
- J/A+A/657/A83
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Cluster strong lensing cosmography is a promising probe of the background geometry of the Universe and several studies have emerged thanks to the increased quality of observations using space- and ground-based telescopes. For the first time, we used a sample of five cluster strong lenses to measure the values of cosmological parameters and combine them with those from classical probes. In order to assess the degeneracies and the effectiveness of strong-lensing cosmography in constraining the background geometry of the Universe, we adopted four cosmological scenarios. We found good constraining power on the total matter density of the Universe ({OMEGA}_m_) and the equation of state of the dark energy parameter w. For a flat wCDM cosmology, we found {OMEGA}_m_=0.30^+0.09^_0.11_ and w=-1.12^+0.17^_0.32_ from strong lensing only. Interestingly, we show that the constraints from the cosmic microwave background (CMB) are improved by factors of 2.5 and 4.0 on {OMEGA}_m_ and w, respectively, when combined with our posterior distributions in this cosmological model. In a scenario where the equation of state of dark energy evolves with redshift, the strong lensing constraints are compatible with a cosmological constant (i.e. {OMEGA}_m_=-1). In a curved cosmology, our strong lensing analyses can accommodate a large range of values for the curvature of the Universe of {OMEGA}_k_=0.28^+0.16^_0.21_. In all cosmological scenarios, we show that our strong lensing constraints are complementary and in good agreement with measurements from the CMB, baryon acoustic oscillations, and Type Ia supernovae. Our results show that cluster strong lensing cosmography is a potentially powerful probe to be included in the cosmological analyses of future surveys.
6915. Galaxy coordinates. II
- ID:
- ivo://CDS.VizieR/J/A+AS/140/89
- Title:
- Galaxy coordinates. II
- Short Name:
- J/A+AS/140/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using images of the Digitized Sky Survey we measured coodinates for 17298 galaxies having poorly defined coordinates. As a control, we measured with the same method 1522 galaxies having accurate coordinates. The comparison with our own measurements shows that the accuracy of the method is about 6 arcsec on each axis (RA and DEC).
- ID:
- ivo://CDS.VizieR/J/ApJ/748/15
- Title:
- Galaxy distances with the Fundamental Manifold
- Short Name:
- J/ApJ/748/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We demonstrate how the Fundamental Manifold (FM) can be used to cross-calibrate distance estimators even when those "standard candles" are not found in the same galaxy. Such an approach greatly increases the number of distance measurements that can be utilized to check for systematic distance errors and the types of estimators that can be compared. Here we compare distances obtained using Type Ia supernova (SN Ia), Cepheids, surface brightness fluctuations, the luminosity of the tip of the red giant branch, circumnuclear masers, eclipsing binaries, RR Lyrae stars, and the planetary nebulae luminosity functions. We find no significant discrepancies (differences are <2{sigma}) between distance methods, although differences at the ~10% level cannot yet be ruled out. The potential exists for significant refinement because the data used here are heterogeneous B-band magnitudes that will soon be supplanted by homogeneous, near-infrared magnitudes. We illustrate the use of FM distances to (1) revisit the question of the metallicity sensitivity of various estimators, confirming the dependence of SN Ia distances on host galaxy metallicity, and (2) provide an alternative calibration of H_0_ that replaces the classical ladder approach in the use of extragalactic distance estimators with one that utilizes data over a wide range of distances simultaneously.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/153
- Title:
- Galaxy environment in the 3D-HST fields (z=0.5-3)
- Short Name:
- J/ApJ/835/153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We make publicly available a catalog of calibrated environmental measures for galaxies in the five 3D-Hubble Space Telescope (HST)/CANDELS deep fields. Leveraging the spectroscopic and grism redshifts from the 3D-HST survey, multiwavelength photometry from CANDELS, and wider field public data for edge corrections, we derive densities in fixed apertures to characterize the environment of galaxies brighter than JH_140_<24mag in the redshift range 0.5<z<3.0. By linking observed galaxies to a mock sample, selected to reproduce the 3D-HST sample selection and redshift accuracy, each 3D-HST galaxy is assigned a probability density function of the host halo mass, and a probability that it is a central or a satellite galaxy. The same procedure is applied to a z=0 sample selected from Sloan Digital Sky Survey. We compute the fraction of passive central and satellite galaxies as a function of stellar and halo mass, and redshift, and then derive the fraction of galaxies that were quenched by environment specific processes. Using the mock sample, we estimate that the timescale for satellite quenching is t_quench_~2-5Gyr; it is longer at lower stellar mass or lower redshift, but remarkably independent of halo mass. This indicates that, in the range of environments commonly found within the 3D-HST sample (M_h_<~10^14^M_{sun}_), satellites are quenched by exhaustion of their gas reservoir in the absence of cosmological accretion. We find that the quenching times can be separated into a delay phase, during which satellite galaxies behave similarly to centrals at fixed stellar mass, and a phase where the star formation rate drops rapidly ({tau}_f_~0.4-0.6Gyr), as shown previously at z=0. We conclude that this scenario requires satellite galaxies to retain a large reservoir of multi-phase gas upon accretion, even at high redshift, and that this gas sustains star formation for the long quenching times observed.
- ID:
- ivo://nasa.heasarc/galexlog
- Title:
- Galaxy Evolution Explorer (GALEX) Observation Log
- Short Name:
- GALEXLOG
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the Galaxy Evolution Explorer (GALEX) observation log of the extant and planned observations to be made by this satellite observatory. The Galaxy Evolution Explorer (GALEX) is a NASA Small Explorer Mission launched on April 28, 2003. GALEX has been performing the first Space Ultraviolet sky survey. Five imaging surveys in each of two bands (FUV: 1350-1750 Angstroms and NUV: 1750-2800 Angstroms) range from an all-sky survey (limiting m<sub>AB</sub> ~ 20 - 21) to an ultra-deep survey of 4 square degrees (limiting m<sub>AB</sub> ~ 26). Three spectroscopic grism surveys (spectral resolution R = 100 - 300) are underway with various depths (m<sub>AB</sub> ~ 20 - 25) and sky coverage (100 to 2 square degrees) over the 1350 - 2800 Angstroms spectral range. The instrument includes a 50-cm modified Ritchey-Chretien telescope, a dichroic beam splitter and astigmatism corrector, two large, sealed-tube microchannel plate detectors to simultaneously cover the two bands and the 1.2-degree field of view. A rotating wheel provides either imaging or grism spectroscopy with transmitting optics. The GALEX mission also includes an Associate Investigator program for additional observations and supporting data analysis which supports a wide variety of investigations made possible by the first UV sky survey. The HEASARC provides this table of GALEX observations as an assistance to the high-energy astrophysics community, e.g., to enable cross-correlations of GALEX with X-ray observations. The GALEX data are available via MAST at <a href="http://galex.stsci.edu/">http://galex.stsci.edu/</a>. More information about GALEX can be found at <a href="http://www.galex.caltech.edu/">http://www.galex.caltech.edu/</a> and <a href="https://asd.gsfc.nasa.gov/archive/galex/">https://asd.gsfc.nasa.gov/archive/galex/</a>. This table was first created in July 2010 using the input file <a href="http://sherpa.caltech.edu/gips/ref/galex_obs_status.csv">http://sherpa.caltech.edu/gips/ref/galex_obs_status.csv</a> obtained from the Caltech GALEX site. This table is updated within a week of the update of the original file. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/ApJ/552/427
- Title:
- Galaxy groups a intermediate redshifts
- Short Name:
- J/ApJ/552/427
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy groups likely to be virialized are identified within the CNOC2, (Yee et al., 2000, Cat. <J/ApJS/129/475>) intermediate-redshift galaxy survey. The resulting groups have a median velocity dispersion, {sigma}1=~200km/s. The virial mass-to-light ratios, using k-corrected and evolution-compensated luminosities, have medians in the range of 150-250h M_{suns}_/L_{sun}_, depending on group definition details. The number-velocity dispersion relation at {sigma}1>~200km/s is in agreement with the low-mass extrapolation of the cluster-normalized Press-Schechter model. Lower velocity dispersion groups are deficient relative to the Press-Schechter model. The two-point group-group autocorrelation function has r0=6.8+/-0.3h^-1^Mpc, which is much larger than the correlations of individual galaxies, but about as expected from biased clustering. The mean number density of galaxies around group centers falls nearly as a power law with r^-2.5^ and has no well-defined core. The projected velocity dispersion of galaxies around group centers is either flat or slowly rising outward. The combination of a steeper than isothermal density profile and the outward rising velocity dispersion implies that the mass-to-light ratio of groups rises with radius if the velocity ellipsoid is isotropic but could be nearly constant if the galaxy orbits are nearly circular. Such strong tangential anisotropy is not supported by other evidence. Although the implication of a rising M/L must be viewed with caution, it could naturally arise through dynamical friction acting on the galaxies in a background of "classical" collisionless dark matter.
- ID:
- ivo://CDS.VizieR/J/MNRAS/412/2498
- Title:
- Galaxy groups and clouds in the local universe
- Short Name:
- J/MNRAS/412/2498
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an all-sky catalogue of 395 nearby galaxy groups revealed in the Local Supercluster and its surroundings. The groups and their associations are identified among 10914 galaxies at |b|>15{deg} with radial velocities V_LG_<3500km/s. Our group-finding algorithm requires the group members to be located inside their zero-velocity surface. Hereby, we assume that individual galaxy masses are proportional to their total K-band luminosities, M/L_K_=6M_{sun}_/L_{sun}_. The sample of our groups, where each group has n>=4 members, is characterized by the following medians: mean projected radius <R>=268kpc, radial velocity dispersion {sigma}_V_=74km/s, K-band luminosity L_K_=1.2x10^11^L_{sun}_, virial and projected masses M_vir_=2.4x10^12^ and M_p_=3.3x10^12^M_{sun}_, respectively. Accounting for measurement error reduces the median masses by 30 per cent. For 97 per cent of identified groups the crossing time does not exceed the cosmic time, 13.7Gyr, with the median at 3.8Gyr. We examine different properties of the groups, in particular of the known nearby groups and clusters in Virgo and Fornax. About a quarter of our groups can be classified as fossil groups where the dominant galaxy is at least 10 times brighter than the other group members.