J/MNRAS/438/2317 Mid-IR QSO spectral templates (Hill+, 2014)
Characterizing quasars in the mid-infrared: high signal-to-noise ratio spectral
templates.
Hill A.R., Gallagher S.C., Deo R.P., Peeters E., Richards G.T.
<Mon. Not. R. Astron. Soc., 438, 2317-2327 (2014)>
=2014MNRAS.438.2317H 2014MNRAS.438.2317H
ADC_Keywords: QSOs ; Spectra, infrared
Keywords: accretion, accretion discs - quasars: emission lines -
quasars: general - infrared: galaxies
Abstract:
Mid-infrared (MIR) quasar spectra exhibit a suite of emission features
including high ionization coronal lines from the narrow-line region
illuminated by the ionizing continuum, broad dust bumps from silicates
and graphites, and polycyclic aromatic hydrocarbon (PAH) features from
star formation in the host galaxy. However, in Spitzer Infared
Spectrograph (IRS) data, few features are detected in most individual
spectra because of typically low signal-to-noise ratios (S/N). By
generating spectral composites from over 180 IRS observations of Sloan
Digital Sky Survey broad-line quasars, we boost the S/N and reveal
features in the complex spectra that are otherwise lost in the noise.
In addition to an overall composite, we generate composites in three
different luminosity bins that span the range of 5.6µm
luminosities of 1040-1046 (erg/s). We detect the high-ionization,
forbidden emission lines of [SIV], [OIV] and [NeV] λ14um in all
templates and PAH features in all but the most luminous template.
Description:
We coordinate cross matched the SDSS quasar catalogue (Schneider et
al., 2010AJ....139.2360S 2010AJ....139.2360S, Cat. VII/260) with the Spitzer (Werner et
al. 2004ApJS..154....1W 2004ApJS..154....1W) Infrared Spectrograph (IRS) archive, using a
match radius of 2 arcsec, yielding 184 low-resolution (R∼60-130) MIR
spectra. We selected all data which had short-low (SL; 5.1-14.3um)
and/or long-low (LL; 13.9-39.9um) modules (although not all objects
necessarily had both modules), opting to keep only the low-resolution
data.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 51 185 *All objects used in generating the mid-IR
and optical composites
table2.dat 38 661 Values for the templates generated from the
objects listed in Table 1
--------------------------------------------------------------------------------
Note on table1.dat: there are only 178 different spectra; see the "Note (1)"
below for details
--------------------------------------------------------------------------------
See also:
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 5 I4 --- Plate Plate SDSS identifier (1)
7- 9 I3 --- Fiber Fiber SDSS identifier (1)
11- 15 I5 --- MJD MJD SDSS identifier (1)
17- 24 I8 --- AORKEY AORKEY Spitzer IRS identifier
26- 30 I5 --- ProgID Program ID Spitzer IRS identifier
32- 36 F5.3 --- z Redshift from Hewett & Wild (2010MNRAS.405.2302H 2010MNRAS.405.2302H,
Cat. J/MNRAS/405/2302)
38- 43 F6.3 [10-7W] logL5.6 [39.7/46.1] 5.6µm luminosity (log(erg/s))
45- 49 F5.1 mag iMAG Absolute i-band magnitude
51 I1 --- Temp [1/3] Template number (2)
--------------------------------------------------------------------------------
Note (1): The object name is not reliable (e.g. names of rows 2 and 3 are
inverted), and should not be used. 7 spectra are moreover duplicated
(the Plate-MJD-Fiber are followed by the bracketted template number):
522-52024-173 (2);
767-52252-418 (2);
1785-54439-615 (3);
2015-53819-251 (3);
2110-53467-104 (1);
2345-53757-410 (1);
2578-54093-195 (2).
Note (2): Template numbers are:
1 = most luminous template
2 = intermediate luminosity template
3 = least luminous template respectively
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.4 um lambda [1.69/34.70] Wavelength
9- 14 F6.4 --- Lnu Total template spectral luminosity
(spectral average of all objects) (1)
16- 22 F7.4 --- Lnu1 ?=-1 Spectral luminosity of most luminous QSOs (1)
24- 30 F7.4 --- Lnu2 ?=-1 Spectral luminosity of intermediate QSOs (1)
32- 38 F7.4 --- Lnu3 ?=-1 Spectral luminosity of least luminous QSOs (1)
--------------------------------------------------------------------------------
Note (1): Luminosities are normalized to the values 14 14µm.
Entries which contain a '-1' indicate no wavelength coverage for
that template.
--------------------------------------------------------------------------------
History:
* 19-Feb-2015: From electronic version of the journal
* 25-Mar-2015: Names suppressed in table1 (from author)
(End) Patricia Vannier [CDS] 05-Dec-2014