Access to Astronomical Catalogues

← Click to display the menu
J/AJ/126/2125       SDSS candidate type II quasars           (Zakamska+, 2003)

Candidate type II quasars from the Sloan Digital Sky Survey. I. Selection and optical properties of a sample at 0.3<z<0.83. Zakamska N.L., Strauss M.A., Krolik J.H., Collinge M.J., Hall P.B., Hao L., Heckman T.M., Ivezic Z., Richards G.T., Schlegel D.J., Schneider D.P., Strateva I., Vanden Berk D.E., Anderson S.F., Brinkmann J. <Astron. J., 126, 2125-2144 (2003)> =2003AJ....126.2125Z
ADC_Keywords: QSOs ; Photometry, SDSS ; Spectroscopy Keywords: galaxies: active - quasars: emission lines - quasars: general - surveys Abstract: Type II quasars are the long-sought luminous analogs of type 2 (narrow emission line) Seyfert galaxies, suggested by unification models of active galactic nuclei (AGNs) and postulated to account for an appreciable fraction of the cosmic hard X-ray background. We present a sample of 291 type II AGNs at redshifts 0.3<z<0.83 from the spectroscopic data of the Sloan Digital Sky Survey. These objects have narrow (FWHM<2000km/s), high equivalent width emission lines with high-ionization line ratios. We describe the selection procedure and discuss the optical properties of the sample. About 50% of the objects have [O III] λ5008 line luminosities in the range 3x108-1010L, comparable to those of luminous (-27<MB←23) quasars; this, along with other evidence, suggests that the objects in the luminous subsample are type II quasars. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 125 291 SDSS Type II AGNs at Redshifts 0.3<z<0.83
See also: J/AJ/123/567 : SDSS quasar catalog, I: Early Data Release (Schneider+, 2002) J/AJ/126/2579 : SDSS quasar catalog. II. First data release (Schneider+, 2003) J/AJ/128/1002 : SDSS candidate type II quasars. II (Zakamska+, 2004) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 4 A4 --- --- [SDSS] 6- 24 A19 --- SDSS The SDSS name (1) 26 I1 --- DR1 [0/1] Availability in Data Release 1 (1 = Yes, 0 = No) 28- 32 F5.3 --- z Redshift based on [O II] (3728) emission line 34- 40 A7 --- TCode The seven-digit target code (2) 42- 46 F5.2 mag u*mag SDSS u*-band PSF magnitude 48- 51 F4.2 mag e_u*mag Error in u*mag 53- 57 F5.2 mag g*mag SDSS g*-band PSF magnitude 59- 62 F4.2 mag e_g*mag Error in g*mag 64- 68 F5.2 mag r*mag SDSS r*-band PSF magnitude 70- 73 F4.2 mag e_r*mag Error in r*mag 75- 79 F5.2 mag i*mag SDSS i*-band PSF magnitude 81- 84 F4.2 mag e_i*mag Error in i*mag 86- 90 F5.2 mag z*mag SDSS z*-band PSF magnitude 92- 95 F4.2 mag e_z*mag Error in z*mag 97- 99 I3 0.1nm EW[OII] Equivalent width of [O II] (3728) 101-104 I4 0.1nm EW[OIII] Equivalent width of [O III] (5008) 106-109 F4.2 [solLum] L[OII] Log of [O II] (3728) luminosity 111-115 F5.2 [solLum] L[OIII] Log of [O III] (5008) luminosity 117-123 F7.2 mJy Flux The FIRST 20cm flux (3) 125 I1 --- Com [0/1] Asymmetric lines (1 = Yes, 0 = No)
Note (1): Coordinates are given in the Name as (J2000). Note (2): The targeting information is in the 5+2 digit target code that shows how the object was targeted for spectroscopy. The first five digits indicate whether the object was targeted on one of the main spectroscopic plates by the Galaxy, LRG, Quasar, High-redshift quasar or Serendipity algorithms, in that order. A digit of 0 means the object was not targeted by this method, while 1 means targeted. The algorithms have different selection criteria and limiting magnitudes, as described in section 2. The last two digits show whether the object was targeted on one of the DSES or one of the Special plates. Note (3): Note on Flux: 0 = Not detected; -1 = The field was not observed by FIRST.
History: From electronic version of the journal References: Zakamska et al., Paper II 2004AJ....128.1002Z, Cat. J/AJ/128/1002
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 19-Dec-2003
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service