J/ApJ/640/579 Near-infrared spectra of 27 SDSS quasars (Glikman+, 2006)
A near-infrared spectral template for quasars.
Glikman E., Helfand D.J., White R.L.
<Astrophys. J., 640, 579-591 (2006)>
=2006ApJ...640..579G 2006ApJ...640..579G
ADC_Keywords: QSOs ; Spectra, infrared
Keywords: quasars: emission lines - quasars: general
Abstract:
We present a near-infrared quasar composite spectrum spanning the
wavelength range 0.58-3.5um. The spectrum has been constructed from
observations of 27 quasars obtained at the NASA IRTF telescope and
satisfying the criteria Ks<14.5 and Mi←23; the redshift range is
0.118<z<0.418. The signal-to-noise ratio is moderate, reaching a
maximum of 150 between 1.6 and 1.9um. While a power-law fit to the
continuum of the composite spectrum requires two breaks, a single
power-law slope of alpha=-0.92 plus a 1260K blackbody provides an
excellent description of the spectrum from Hα to 3.5um, strongly
suggesting the presence of significant quantities of hot dust in this
blue-selected quasar sample. We measure intensities and line widths
for 10 lines, finding that the Paschen line ratios rule out case B
recombination. We compute K-corrections for the J, H, K, and Spitzer
3.6um bands, which will be useful in analyzing observations of quasars
up to z=10.
Description:
We obtained near-infrared spectra for 27 of the quasars. All spectra
but one were obtained at the NASA Infrared Telescope Facility (IRTF),
a 3.0m telescope optimized for infrared observations on the summit of
Mauna Kea, Hawaii.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 74 27 List of studied QSOs
table3.dat 31 7740 Composite quasar spectrum, arithmetic and
geometric means
table7.dat 31 10944 Optical-to-infrared composite quasar spectrum,
arithmetic and geometric means
table8.dat 31 100 Quasar K-corrections
sp/* . 27 Individual spectra
--------------------------------------------------------------------------------
See also:
VII/252 : SDSS-DR5 quasar catalog (Schneider+, 2007)
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS name (JHHMMSS.ss+DDMMSS.s)
26- 27 I2 h RAh Right ascension (J2000)
29- 30 I2 min RAm Right ascension (J2000)
32- 36 F5.2 s RAs Right ascension (J2000)
38 A1 --- DE- Declination sign (J2000)
39- 40 I2 deg DEd Declination (J2000)
42- 43 I2 arcmin DEm Declination (J2000)
45- 48 F4.1 arcsec DEs Declination (J2000)
52- 74 A23 --- FileName Name of the spectra file in sp subdirectory
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table[37].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.1 0.1nm Lambda Wavelength in Angstroms
9- 15 F7.4 --- Flux Arithmetic mean flux in arbitrary units
17- 23 F7.4 --- e_Flux Error in Flux
25- 31 F7.4 --- GFlux Geometric mean flux in arbitrary units
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 F4.1 --- z Redshift
6- 10 F5.3 mag Kc(J) ? 2MASS J band K-correction
12- 17 F6.3 mag Kc(H) ? 2MASS H band K-correction
19- 24 F6.3 mag Kc(K) ? 2MASS KS band K-correction
26- 31 F6.3 mag Kc(3.6) Spitzer IRAC 3.6 micron band K-correction
--------------------------------------------------------------------------------
Byte-by-byte Description of file: sp/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.6 um Lambda Wavelength
10- 21 E12.5 --- Flux Flux in arbitrary units
23- 33 E11.5 --- e_Flux Error in Flux in arbitrary units
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 26-Sep-2008