FRIICAT - FIRST Catalog of FR II Radio Galaxies
The radio luminosity at 1.4 GHz of the FRIICAT sources covers the range L1.4 ~ 1039.5 - 1042.5 erg/s. The FRIICAT catalog has 90% of low- and 10% of high-excitation galaxies (LEGs and HEGs), respectively. The properties of these two classes are significantly different. The FRIICAT LEGs are mostly luminous (-20 >~ Mr >~ -24), red early-type galaxies with black hole masses in the range 108 Msun <~ MBH <~ 109 M_sun_; they are essentially indistinguishable from the FR Is belonging to the FRICAT sample (Capetti et al. 2017, A&A, 598, A49: also available as a HEASARC table). The HEG FR IIs are associated with optically bluer and mid-IR redder hosts than the LEG FR IIs and to galaxies and black holes that are smaller, on average, by a factor of ~2. FR IIs have a factor of ~3 higher average radio luminosity than FR Is. Nonetheless, most (~90%) of the selected FR IIs have a radio power that is lower, by as much as a factor of ~100, than the transition value between FR Is and FR IIs found in the 3C sample. The correspondence between the morphological classification of FR I and FR II and the separation in radio power disappears when including sources selected at low radio flux thresholds, which is in line with previous results. In conclusion, a radio source produced by a low-power jet can be edge brightened or edge darkened, and the outcome is not related to differences in the optical properties of the host galaxy.
The authors searched for FR II radio galaxies in the sample of 18,286 radio sources built by Best & Heckman (2012, MNRAS, 421, 1569) by limiting their search to the subsample of objects in which, according to these latter authors, the radio emission is produced by an active nucleus. They cross-matched the optical spectroscopic catalogs produced by the group from the Max Planck Institute for Astrophysics and Johns Hopkins University (Brinchmann et al. 2004, MNRAS, 351, 1151; Tremonti et al. 2004, ApJ, 613, 898) based on data from the Data Release 7 of the Sloan Digital Sky Survey (DR7/SDSS; Abazajian et al. 2009, ApJS, 182, 543) with the National Radio Astronomy Observatory Very Large Array Sky Survey (NVSS; Condon et al. 1998, AJ, 115, 1693, CDS Cat. VIII/65) and the Faint Images of the Radio Sky at Twenty centimeters survey (FIRST; Becker et al. 1995, ApJ, 450, 559; Helfand et al. 2015, ApJ, 801, 26, CDS Cat. VIII/92) adopting a radio flux density limit of 5 mJy in the NVSS. The authors focused on those sources with redshift z < 0.15.
The majority (108) of the selected FR IIs are classified as LEG, but there are also 14 HEG and just one source that cannot be classified spectroscopically because of the lack of emission lines, namely SDSS J144625.13+214209.8.
Throughout this study, the authors adopted a cosmology with H0 = 67.8 km s-1 Mpc-1, OmegaM = 0.308, and OmegaLambda = 0.692 (Planck Collaboration XIII 2016, A&A, 594, A13).
FRIICAT: A FIRST catalog of FR II radio galaxies. Capetti A., Massaro F., Baldi R.D. <Astron. Astrophys. 601, A81 (2017)> =2017A&A...601A..81C (SIMBAD/NED BibCode)
The J2000.0 position-based SDSS source designation, viz., SDSS JHHMMSS.ss+DDMMSS.s.
The Right Ascension of the radio galaxy in the selected equinox. This was given to an implicit precision of 0.01 seconds of time in the SDSS name.
The Declination of the radio galaxy in the selected equinox. This was given to an implicit precision of 0.1 arcseconds in the SDSS name.
The Galactic Longitude of the radio galaxy.
The Galactic Latitude of the radio galaxy.
The redshift of the radio galaxy, taken from Best & Heckman (2012, MNRAS, 421, 1569).
The NVSS 1.4-GHz flux density of the radio galaxy, in mJy, taken from Best & Heckman (2012, MNRAS, 421, 1569).
The [OIII] line flux of the radio galaxy, in erg s-1 cm-2, taken from the MPA-JHU DR7 release of spectrum measurements.
The SDSS DR7 r-band AB magnitude of the radio galaxy, corrected for Galactic extinction, taken from the MPA-JHU DR7 release of spectrum measurements.
The Dn(4000) spectroscopic index of the radio galaxy, taken from the MPA-JHU DR7 release of spectrum measurements. Dn(4000) is defined according to Balogh et al. (1999, ApJ, 527, 54) as the ratio between the flux density measured on the "red" side of the Ca II break (4000-4100 Angstroms) and that on the "blue" side (3850-3950 Angstroms). Low redshift (z < 0.1) red galaxies show Dn(4000) = 1.98 +/- 0.05, which is a value that decreases to 1.95 +/- 0.05 for 0.1 < z < 0.15 galaxies (Capetti & Raiteri 2015, A&A, 580, A73). The presence of young stars or of non-stellar emission reduces the Dn(4000) index. The authors estimate a median error of 0.03 for the Dn(4000) index values quoted herein.
The stellar velocity dispersion of the radio galaxy sigma*, in km s-1, taken from the MPA-JHU DR7 release of spectrum measurements. The authors estimate a median error of 10 km s-1 for the stellar dispersion values quoted herein.
The concentration index Cr of the radio galaxy taken directly from the SDSS database. The authors estimate a median error of 0.09 for the concentration index values quoted herein. The concentration index Cr is defined as the ratio of the radii including 90% and 50% of the light in the r band, respectively. Early-type galaxies (ETGs) have higher values of Cr than do late-type galaxies. Two thresholds have been suggested to define ETGs: a more conservative value at Cr >~ 2.86 and a more relaxed selection at Cr >~ 2.6. See Section 3.1 of the reference paper for more details.
The logarithm of the radio luminosity nu*L(nu) at 1.4 GHz, in erg s-1, calculated from the 1.4-GHz flux density and the redshift of the radio galaxy using the Planck-derived cosmological parameters listed in the Overview above.
The logarithm of the [O III] line luminosity, in erg s-1, calculated from the [O III] flux and the redshift of the radio galaxy using the Planck-derived cosmological parameters listed in the Overview above.
The logarithm of the black hole mass MBH in the radio galaxy, in solar masses. The black hole masses were estimated by the authors from the stellar velocity dispersion and the sigma* - MBH relation of Tremaine et al. (2002, ApJ, 574, 740). The uncertainties in the MBH values are dominated by the spread of the relation used (rather than by the errors in the measurements of sigma*, resulting in an uncertainty of a factor of ~2.
The spectroscopic classification of the radio galaxy (from Best & Heckman 2012, MNRAS, 421, 1569), low-excitation galaxy (LEG) versus high-excitation galaxy (HEG), based on the optical emission line ratios in their SDSS spectra. Just one source cannot be classified spectroscopically because of the lack of emission lines, namely SDSS J144625.13+214209.8.