The third release of the Large Quasar Astrometric Catalog (LQAC-3): a compilation of 321 957 objects

Abstract

Context. From an astrometric point of view, quasars constitute quasi-ideal reference objects in the celestial sphere, with an a priori absence of proper motion. Since the second release of the Large Quasar Astrometric Catalog (LQAC), a large number of quasars have been discovered, in particular with the upcoming new release of the SDSS quasars catalog. Aims. Following the same procedure as in the two previous releases of the LQAC, our aim was to compile all the quasars recorded until the present date, with accurate recomputation of their equatorial coordinates in the ICRS and with the maximum of information concerning their physical properties, such as the redshift, the photometry, and the absolute magnitudes. Methods. For the purpose above, we carried out the cross-identification between the 9 catalogs of quasars chosen for their huge number of objects, including all the available data related to magnitudes, radiofluxes, and redshifts. This cross identification was particularly delicate because of a slight change in coordinates between the objects common to two successive releases of the SDSS and the elimination of some of them. Equatorial coordinates were recomputed more accurately according to the algorithms used for the elaboration of the Large Quasar Reference Frame (LQRF). Moreover, absolute magnitudes and morphological indexes of the new objects were given, following the same method as in the LQAC-2. Results. Our final catalog, called LQAC-3, contains 321 957 objects including a small proportion of AGNs (14 128) and BLLac (1183). This is roughly 70% more than the number of objects recorded in the LQAC-2. Conclusions. The LQAC-3 will be useful for the astronomical community since it gives the most complete information available about the whole set of already recorded quasars, with emphasis on the precision and accuracy of their coordinates with respect to the ICRF2.

The formation of ultra compact dwarf galaxies and massive globular clusters

“…There are several noticeable features in this figure: (i) for the MKDP IMF, UCDs with initial stellar mass M UCD 10 8 M are as bright as quasars (Dunlop et al 1993(Dunlop et al , 2003Souchay et al 2015) for the first few 10 7 yr. We use low-redshift quasars because for these we were able to find bolometric luminosities, but also absolute magnitudes in the V and I band. We note, however, that high redshift quasars show very comparable luminosities as shown for example by Mortlock et al (2011).…”

“…We have not found any publication or catalogue presenting both the absolute magnitudes in the V filter, M V , and I filter, M I . Therefore, the data in the table use the catalogue by Souchay et al (2015) containing the M I values. The M V values are taken from Dunlop et al (1993) and Dunlop et al (2003).…”

“…The η value affects the estimates of the number of SNe Ia and also of the ejecta (Thielemann et al 1986;Greggio & Renzini 1983;Matteucci & Greggio 1986). The computed rates The grey panel shows the typical luminosities of quasars (Dunlop et al 1993(Dunlop et al , 2003Souchay et al 2015) and the brown panel shows the luminosity span for the peak luminosities supernovae ( …”

“…We consider 10 7 , 10 8 , 10 9 M as initial stellar masses, and metallicity values [Fe/H] = −2, 0. Here we show only the results for the MKDP IMF plotted together with the quasar data (black cross and plus markers, cross for radio quiet and plus for radio loud quasars) from Dunlop et al (1993Dunlop et al ( , 2003; Souchay et al (2015). The data are compiled in Table 3.…”

Identifying quasars with astrometric and mid-infrared methods from APOP and ALLWISE

“…The newly released third Large Quasars Astrometric Catalog (hereafter LQAC3, Souchay et al 2015) includes most of the confirmed quasars. We cross-matched APOP with LQAC3 and estimated the zero-point as a comparison.…”