X-ray Selected BL Lacertae Objects: Catalogue and Statistical Properties
B. Z. Kapanadze
备注：
5 pages, 2 figures, invited lecture at "Young Scientits' Conference on Astronomy and Space Physics", Kiev, Taras Shevchenko National University,2011, May 2-7
This talk focuses on the statistical properties of X-ray selected BL Lacertae objects (XBLs) whose catalogue has been compiled. It consists of 312 sources from different X-ray surveys, unambiguously identified to mid-2010. Results of the statistical research of different observational quantities (redshift, muliwavelength luminosities, host/nucleus absolute Magnitudes, central black hole masses, synchrotron peak frequencies, broadband spectral indices) are also provided and existence of the correlation between them is proved. Overall flux variability shows an increasing trend towards greater frequencies. XBL are found to be much less active in point of intra-night optical variability compared to radio-selected BL Lacs (RBLs). A separate list of 106 XBL candidates is also created including the same characteristics for each source as in the case of XBL catalogue.
The cosmological utility of galaxy cluster catalogues is primarily limited by our ability to calibrate the relation between halo mass and observable mass proxies such as cluster richness, X-ray luminosity or the Sunyaev-Zeldovich signal. Projection effects are a particularly pernicious systematic effect that can impact observable mass proxies; structure along the line of sight can both bias and increase the scatter of the observable mass proxies used in cluster abundance studies. In this work, we develop an empirical method to characterize the impact of projection effects on redMaPPer cluster …
Cosmological probes based on galaxy clusters rely on cluster number counts and large-scale structure information. X-ray cluster surveys are well suited for this purpose, since they are far less affected than optical surveys by projection effects, and cluster properties can be predicted with good accuracy. The XMM Cluster Archive Super Survey, X-CLASS, is a serendipitous search of X-ray-detected galaxy clusters in 4176 XMM-Newton archival observations until August 2015. All observations are clipped to exposure times of 10 and 20 ks to obtain uniformity and they span ~269 deg$^2$ across the high…
X-ray counterparts for 35 galaxy clusters contained in the PF catalog of galaxy clusters and groups were found in XMM-Newton archive. 22 ones (all from ACO catalogue) have extended elliptic X-ray haloes appropriate for determination of orientation. Position angles and eccentricities were calculated and compared with cluster orientations optical band.
4098 galaxy clusters to z~0.6 in the Sloan Digital Sky Survey equatorial Stripe 82
我们提出了一个星表的4098光度选择的星系团的中值红移<z>= 0.32在270平方度的“条纹82”的区域的斯隆数字巡天（SDSS），覆盖天球赤道南银河帽（-50 < RA < 59度，|Dec| < 1.25度）。由于该区域的多历元SDSS覆盖，ugriz测光比主要SDSS足迹内的单次扫描深约2个星等。我们利用这一点来检测星系团使用的算法，搜索统计上显着overdensities的星系在Voronoi镶嵌的投影天空。32%的星团至少有一个成员的光谱红移来自现有的公开数据（SDSS Data Release 7，2SLAQ & WiggleZ），其余的具有稳健的光度红移（在样本的中值红移处精确到约5-9%）。成员星系红移的加权平均值提供了一个相当准确的星系团红移的估计。集群目录是公开的，可供社区利用，以追求一系列科学目标。除了星团目录，我们还提供了一个18,295 V<21等类星体视线的链接目录，其碰撞参量在<3 Mpc的星团核心内，这些星团核心选自Veron等人（2010）的目录。背景类星体覆盖0.25 < z < 2，其中与团簇相关的MgII吸收线系统在光谱中是可检测的。
The North-Ecliptic Pole is an important region for extragalactic surveys. Deep/wide contiguous surveys are being performed by several space observatories. We analyse all ROSAT pointed and survey observations within 40 deg2 around the NEP, restricting the field-of-view to the inner 30' radius. We obtain an X-ray catalogue of 805 sources with 0.5-2 keV fluxes >2.9E-15 cgs, a factor of three deeper than the ROSAT All-Sky Survey in this field. The sensitivity and angular resolution of our data are comparable to the eROSITA All-Sky Survey expectations. We use HEROES optical and near-infrared imagin…
SPIDERS is the spectroscopic follow-up effort of the Sloan Digital Sky Survey IV (SDSS-IV) project for the identification of X-ray selected galaxy clusters. We present our catalogue of 2740 visually inspected galaxy clusters as a part of the SDSS Data Release 16 (DR16). Here we detail the target selection, our methods for validation of the candidate clusters, performance of the survey, the construction of the final sample, and a full description of what is found in the catalogue. Of the sample, the median number of members per cluster is approximately 10, with 818 having 15 or greater. We find…
Past studies of compact active galactic nuclei (AGNs), the dominant population at high radio frequencies, selected them using flat spectral index criteria. This biases the sample due to the steepening of AGN spectra at high radio frequencies. We improve upon this by selecting 3610 compact AGNs using their angular size information ($\sim$0.15 arcsec scale) from the Australia Telescope 20 GHz (AT20G) high-angular-resolution catalogue. We cross-match these against the Wide-field Infrared Survey Explorer All-WISE catalogue and present a catalogue with 3300 (91%) matches, 91 (3%) rejects and 219 (6…
