J/ApJ/751/52 AGN candidates from the WISE, 2MASS, RASS (W2R) (Edelson+, 2012)
Reliable identifications of active galactic nuclei from the WISE, 2MASS, and
ROSAT all-sky surveys.
Edelson R., Malkan M.
<Astrophys. J., 751, 52 (2012)>
=2012ApJ...751...52E 2012ApJ...751...52E
ADC_Keywords: Active gal. nuclei ; Cross identifications ; X-ray sources ;
Photometry, infrared ; Redshifts
Keywords: galaxies: active - galaxies: Seyfert - methods: statistical -
quasars: general - surveys
Abstract:
We have developed the "SIX" statistic to identify bright, highly
likely active galactic nucleus (AGN) candidates solely on the basis of
Wide-field Infrared Survey Explorer (WISE), Two Micron All-Sky Survey
(2MASS), and ROSAT all-sky survey (RASS) data. This statistic was
optimized with data from the preliminary WISE survey and the Sloan
Digital Sky Survey, and tested with Lick 3m Kast spectroscopy. We find
that sources with SIX<0 have a ≳95% likelihood of being an AGN
(defined in this paper as a Seyfert 1, quasar, or blazar). This
statistic was then applied to the full WISE/2MASS/RASS dataset,
including the final WISE data release, to yield the "W2R" sample of
4316 sources with SIX<0. Only 2209 of these sources are currently in
the Veron-Cetty and Veron (VCV) catalog of spectroscopically confirmed
AGNs, indicating that the W2R sample contains nearly 2000 new,
relatively bright (J≲16) AGNs. We utilize the W2R sample to quantify
biases and incompleteness in the VCV catalog. We find that it is
highly complete for bright (J<14), northern AGNs, but the completeness
drops below 50% for fainter, southern samples and for sources near the
Galactic plane. This approach also led to the spectroscopic
identification of 10 new AGNs in the Kepler field, more than doubling
the number of AGNs being monitored by Kepler. The W2R sample contains
better than 1 bright AGN every 10 deg2, permitting construction of
AGN samples in any sufficiently large region of sky.
Description:
We observed seven sources in the bright AGN test sample that meet the
selection criteria from the WISE, 2MASS, RASS, but that are not in the
VCV catalog (Cat. VII/258) on 2011 December 19 and 20 with the Kast
double spectrograph on the Shane 3m reflector.
Our group utilized the methods of Stocke et al. (1983ApJ...273..458S 1983ApJ...273..458S),
Malkan (2004ASPC..311..449M 2004ASPC..311..449M), and an earlier incarnation of the SIX
technique to identify and begin to monitor an additional 13 AGNs in
the Kepler field. These now have spectroscopic confirmations from the
Kast double spectrograph on the Lick 3m telescope. The observations,
obtained in 2011 July, were reduced in the same way as for the 2011
December run, except that the slit width was 2.0', affording slightly
better spectral resolution.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 116 77 *Bright AGN test sample
table3.dat 119 4316 Sources in the W2R (WISE/2MASS/RASS) sample of
highly-likely AGN candidates
table4.dat 88 13 Lick spectroscopy of Kepler field AGNs
table5.dat 86 55050 The "W2" (WISE/2MASS) sample of
moderate-likelihood AGN candidates
--------------------------------------------------------------------------------
Note on table2.dat: Sources in this table meet the following criteria:
detected at >10σ in all WISE and 2MASS bands, the discriminator
statistics infra-red-X SIX<0, J<14, right ascension between 21h and
15h, and declination >-20°. Of the 77 sources in this list, 70 are
also listed in the VCV catalog (Cat. VII/258). The remaining seven
sources were observed with the Lick 3m. Table is sorted in ascending
order in SIX.
--------------------------------------------------------------------------------
See also:
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
J/ApJS/208/24 : Spitzer MIR AGN survey. I. (Lacy+, 2013)
J/AJ/144/11 : Nuclear SEDs, Spitzer spectra of 22 AGNs (Mason+, 2012)
J/MNRAS/425/1215 : Multiwavelength survey of AGNs (Klesman+, 2012)
J/A+A/525/A127 : Properties of X-ray selected AGNs (Tasse+, 2011)
J/ApJ/708/584 : SEXSI Spitzer catalog (Eckart+, 2010)
J/ApJ/717/1181 : Spitzer power-law galaxies in EGS (Park+, 2010)
J/ApJ/680/130 : Mid-IR colors of AGNs in the MUSYC ECDF-S (Cardamone+, 2008)
J/AJ/128/1002 : SDSS candidate type II quasars. II (Zakamska+, 2004)
J/A+A/418/465 : Mid-infrared and hard X-ray emission in AGN (Lutz+, 2004)
J/ApJ/610/128 : NIR colors of hard X-ray-selected AGN (Watanabe+, 2004)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq [1/77] Running sequence number
4- 20 A17 --- VCV Source name in the VCV catalog (VII/258) if any
22- 23 I2 h RAh WISE hour of right ascension (J2000)
25- 26 I2 min RAm WISE minute of right ascension (J2000)
28- 32 F5.2 s RAs WISE second of right ascension (J2000)
34 A1 --- DE- WISE sign of declination (J2000)
35- 36 I2 deg DEd WISE degree of declination (J2000)
38- 39 I2 arcmin DEm WISE arcminute of declination (J2000)
41- 44 F4.1 arcsec DEs WISE arcsecond of declination (J2000)
46- 50 F5.2 mag Jmag [11.9/14] Measured J-band magnitude
52- 57 F6.3 --- SIX [-1.4/-0.002] SIX figure of merit
parameterization (G1)
59- 63 F5.3 --- SI [0.01/1] SI figure of merit
parameterization (G1)
65- 70 F6.3 [-] logSX [-1.9/0.7] Log of SX figure of merit
parameterization (G1)
72- 75 A4 --- Type AGN type
77- 81 F5.3 --- z [0.006/1.4]? Redshift
83- 92 I10 --- 2MASS 2MASS identification number
94- 97 A4 --- --- [1RXS]
99-114 A16 --- 1RXS RASS name (JHHMMSS.s+DDMMSS)
116 I1 --- n_Seq [1/2]? New or non-AGN source (G2)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Seq [1/4316] Running sequence number
6- 15 I10 --- 2MASS 2MASS identification number
17- 18 I2 h RAh Hour of Right Ascension (J2000)
20- 21 I2 min RAm Minute of Right Ascension (J2000)
23- 27 F5.2 s RAs Second of Right Ascension (J2000)
29 A1 --- DE- Sign of the Declination (J2000)
30- 31 I2 deg DEd Degree of Declination (J2000)
33- 34 I2 arcmin DEm Arcminute of Declination (J2000)
36- 39 F4.1 arcsec DEs Arcsecond of Declination (J2000)
41- 46 F6.3 mag Jmag [11.7/17] 2MASS J band magnitude
48- 53 F6.3 --- SIX [-2.4/0] SIX figure of merit
parameterization (G1)
55- 59 F5.3 --- SI [0/1] SI figure of merit parameterization (G1)
61- 66 F6.3 [-] logSX [-4.1/1] Log of SX figure of merit
parameterization (G1)
68- 71 A4 --- --- [1RXS]
73- 88 A16 --- 1RXS RASS catalog identifier (JHHMMSS.s+DDMMSS)
90-106 A17 --- VCV VCV catalog identifier (Veron VII/258)
108-111 A4 --- Type VCV catalog type (Veron+, Cat. VII/258)
113-117 F5.3 --- z [0.006/2.5]? VCV catalog redshift (VII/258)
119 I1 --- n_Seq [1/2]? New or non-AGN source (G2)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq [1/13] Running sequence number
4- 14 A11 --- ID Source identifier (1)
16- 17 I2 h RAh Hour of Right Ascension (J2000)
19- 20 I2 min RAm Minute of Right Ascension (J2000)
22- 26 F5.2 s RAs Second of Right Ascension (J2000)
28 A1 --- DE- Sign of the Declination (J2000)
29- 30 I2 deg DEd Degree of Declination (J2000)
32- 33 I2 arcmin DEm Arcminute of Declination (J2000)
35- 38 F4.1 arcsec DEs Arcsecond of Declination (J2000)
40- 45 F6.3 --- SIX [-0.7/1.3]? SIX figure of merit
parameterization (G1)
47- 51 F5.2 mag Jmag [14/16.1] 2MASS J-band magnitude
53- 57 F5.3 --- z [0.06/0.7] Redshift
59- 66 I8 --- KIC Kepler identification number
68- 88 A21 --- Comm Comments (2)
--------------------------------------------------------------------------------
Note (1): The first 10 sources are in the W2R sample; they are sorted by SIX.
The next fell slightly outside the cutoff but is in the W2 sample.
The last two were not included in either sample; they were initially
found by the techniques of Stocke et al. (1983ApJ...273..458S 1983ApJ...273..458S) and
Malkan (2004ASPC..311..449M 2004ASPC..311..449M).
Note (2): Indicate the strongest spectral features identified in each spectrum,
which were used to derive the redshift. In nearly all cases they are
emission lines (except for the stellar absorption lines found in the
one BL Lac object).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- Seq [1/55050] Running sequence number;
sorted by increasing SI
7- 16 I10 --- 2MASS 2MASS identification number
18- 19 I2 h RAh Hour of Right Ascension (J2000)
21- 22 I2 min RAm Minute of Right Ascension (J2000)
24- 28 F5.2 s RAs Second of Right Ascension (J2000)
30 A1 --- DE- Sign of the Declination (J2000)
31- 32 I2 deg DEd Degree of Declination (J2000)
34- 35 I2 arcmin DEm Arcminute of Declination (J2000)
37- 40 F4.1 arcsec DEs Arcsecond of Declination (J2000)
42- 47 F6.3 mag Jmag [9.5/17] 2MASS J band magnitude
49- 53 F5.3 --- SI [0/1.8] Figure of merit parameterization (G1)
55- 71 A17 --- VCV The VCV catalog name (Veron VII/258)
73- 76 A4 --- Type Source type (Veron VII/258)
78- 82 F5.3 --- z [0.001/4]? Redshift
84 A1 --- f_z [N] Indicates redshift is not available
86 I1 --- n_Seq [1/2]? New or non-AGN source (G2)
--------------------------------------------------------------------------------
Global notes:
Note (G1): The figure-of-merit parameterization of the infrared colors is
denoted as SI as in equation (4): SI=1.7c2+2.0c3+c4 A low
score indicates a high likelihood that the source is an AGN, and the
result is positive-definite (see section 2.4). A second parameter SX
based on the WISE-RASS source distance is defined in equation (5) as:
SX=(d/e)2 where d is the distance from the WISE source to the
nearest RASS source and e is the uncertainty in d (a typical RASS
source positional uncertainty is e=15arcsec; see section 2.5).
SIX is defined from SI and SX as (equation (6) in section 2.6):
SIX=log10(SI+0.116SX)
Note (G2): Flag as follows:
1 = Newly identified source observed with the Lick 3m and not listed in the
VCV catalog (Cat. VII/258). The identification and redshift estimation is
based on spectra in Figure 3 and the source name is denoted by a
positional name.
2 = The source listed in the VCV catalog (Cat. VII/258) is not compatible
with this paper's definition of an AGN.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 17-Dec-2013