J/other/NewA/11.27 2MASS observation of BL Lac objects (Chen+, 2005)
2MASS observation of BL Lac objects.
Chen P.S., Fu H.W., Gao Y.F.
<New Astronomy, 11, 27-42 (2005)>
=2005NewA...11...27C 2005NewA...11...27C
ADC_Keywords: BL Lac objects ; Infrared sources ; Photometry, infrared
Keywords: galaxies: AGN, BL Lac object - infrared: galaxies
Abstract:
The 2MASS observations of known BL Lac objects are presented in this
paper. The 2MASS associations for 511 BL Lac objects are identified.
From the 2MASS near infrared two-color diagram it is seen that
majority (about 70%) of objects are lying alone with or very close to
the power law distribution implying that there is no need to invoke
any significant radiation mechanism additional to a power law
continuum for those sources. However, many sources (about 30%) are
still located very close to the blackbody distribution indicative of
the possible contributions from the host galaxies. In addition, the
average spectral index derived for the near infrared region is
0.66±0.34 that is rather smaller than that from the previous results
indicative of the possible influence from the host galaxies and/or
from the lack or weakness of the radio emissions from most sources
newly discovered by recent X-ray missions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 151 511 2MASS observations of BL Lac objects
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/252 : The USNO-A2.0 Catalogue (Monet+ 1998)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
J/other/NewA/11.557 : BL Lac objects infrared photometry (Chen+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Sequential number
5- 21 A17 --- Name BL Lac object Name
23- 35 A13 --- USNO USNO-A2 or USNO-B1 number
36 A1 --- n_USNO [AB] USNO-A2 (A) or USNO-B1 (B)
38- 39 I2 h RAh 2MASS Right ascension (J2000)
41- 42 I2 min RAm 2MASS Right ascension (J2000)
44- 48 F5.2 s RAs 2MASS Right ascension (J2000)
50 A1 --- DE- 2MASS Declination sign (J2000)
51- 52 I2 deg DEd 2MASS Declination (J2000)
54- 55 I2 arcmin DEm 2MASS Declination (J2000)
57- 60 F4.1 arcsec DEs 2MASS Declination (J2000)
62- 65 F4.2 arcsec r1 Distance between BL Lac object and
related USNO source
67- 70 F4.2 arcsec r2 Distance between USNO source and
related 2MASS source
72- 76 F5.2 mag Vmag ? V magnitude
78- 83 F6.3 mag Jmag 2MASS J magnitude
84 A1 --- n_Jmag [*] * indicates an upper limit for Jmag
86- 90 F5.3 mag e_Jmag ? rms uncertainty on Jmag
92- 97 F6.3 mag Hmag 2MASS H magnitude
98 A1 --- n_Hmag [*] * indicates an upper limit for Hmag
100-104 F5.3 mag e_Hmag ? rms uncertainty on Hmag
106-111 F6.3 mag Kmag 2MASS K magnitude
112 A1 --- n_Kmag [*] * indicates an upper limit for Kmag
114-118 F5.3 mag e_Kmag ? rms uncertainty on Kmag
120-124 F5.2 --- alpha(J-K) ? Power spectral index between J and K bands
126-130 F5.3 --- z ? Redshift
132-136 A5 --- Type Type of object (1)
139-141 A3 --- rad [*st ] Radio note (2)
142 A1 ---- u_Av [)] Uncertainty flag on Av
143-147 F5.3 mag Av ? Interstellar extinction coefficient Av
151 A1 --- Host [#] #: possible influence from the host galaxy
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Note (1): Type of object as follows:
BL = confirmed BL Lac object
BL? = probable BL Lac object
pBL = possible BL Lac object
? = questionable BL Lac object
HP = highly polarized BL Lac object
Note (2): Radio note as follows:
* = source not detected in the radio band
*st = source not detected in the radio band, star
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 23-Jun-2006