Redshift of the Fermi Flaring Blazar PMN J2331-2148
ATel #2206; J. P. Halpern, A. P. S. Crotts (Columbia U.)
on 20 Sep 2009; 18:20 UT
Credential Certification: Jules Halpern (jules@astro.columbia.edu)
Subjects: Optical, Gamma Ray, >GeV, AGN, Quasar
Longo et al. (ATel #2101) reported a Fermi LAT detection of flaring
from the flat-spectrum radio source PMN J2331-2148, of unknown
redshift, on 2009 June 26.
The optical counterpart of PMN J2331-2148 is visible on the
Digitized Sky Survey with position from the USNO B1.0 catalog
RA = 23h31m04.03s, Decl.=-21d48'15.3" (J2000.0). We obtained
six 10 minute spectra using the Boller & Chivens CCD Spectrograph
on the 2.4m Hiltner Telescope of the MDM Observatory on 2009
September 18, covering the wavelength range 3860-7530 Angstroms.
Emission lines of the Balmer series and Mg II 2795,2802 are detected
at z=0.563+/-0.002, superposed on a blue continuum.
Based on the -18 Angstroms equivalent width of of Mg II,
we classify PMN J2331-2148 as a flat-spectrum radio quasar.
