J/ApJ/703/1778 Spitzer sources in SWIRE/XMM/ELAIS-S1 field (Sacchi+, 2009)
Spectroscopic identifications of Spitzer sources in the
SWIRE/XMM-Newton/ELAIS-S1 field: a large fraction of active galactic nucleus
with high F(24µm)/F(R) ratio.
Sacchi N., La Franca F., Feruglio C., Fiore F., Puccetti S., Cocchia F.,
Berta S., Brusa M., Cimatti A., Comastri A., Franceschini A., Gruppioni C.,
Maiolino R., Matute I., Polletta M., Pozzetti L., Pozzi F., Vignali C.,
Zamorani G., Oliver S., Rowan-Robinson M., Smith G., Lonsdale C.
<Astrophys. J., 703, 1778-1790 (2009)>
=2009ApJ...703.1778S 2009ApJ...703.1778S
ADC_Keywords: Surveys ; Galaxies, IR ; Active gal. nuclei ; Redshifts
Keywords: galaxies: active - infrared: galaxies - surveys
Abstract:
We present a catalog of optical spectroscopic identifications of
sources detected by Spitzer at 3.6 or 24um down to ∼10 and ∼280uJy,
respectively, in the SWIRE/XMM-Newton/ELAIS-S1 field and classified
via line width analysis and diagnostic diagrams. A total of 1376
sources down to R∼24.2mag have been identified (1362 detected at
3.6um, 419 at 24um, and 405 at both) by low-resolution optical
spectroscopy carried out with FORS2, VIMOS, and EFOSC2 at the Very
Large Telescope and 3.6m ESO telescope. The spectroscopic campaigns
have been carried out over the central 0.6deg2 area of ELAIS-S1
which, in particular, has also been observed by XMM-Newton and
Chandra. We find the first direct optical spectroscopic evidence that
the fraction of active galactic nuclei (AGNs; mostly AGN2) increases
with increasing F(24um)/F(R) ratio, reaching values of 70(±20)% in
the range 316<F(24um)/F(R)<1000. We present an Infrared Array
Camera-Multiband Imaging Photometer color-color diagram able to
separate AGN1 from obscured AGN2 candidates. After having corrected
for the spectroscopic incompleteness of our sample, the result is that
the AGN fraction at F(24um)∼0.8mJy is ∼22(±7)% and decreases slowly
to ∼19(±5)% down to F(24um)∼0.3mJy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 108 1376 The spectroscopic catalog
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See also:
J/A+A/451/881 : ESIS BVR catalog, ELAIS-S1 (Berta+, 2006)
J/A+A/457/501 : XMM-Newton survey of the ELAIS-S1 field. I. (Puccetti+, 2006)
J/A+A/488/417 : XMM-Newton survey of the ELAIS-S1 field. II. (Feruglio+, 2008)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq Running identification number
6- 25 A20 --- ESIS ESIS identification from Berta et al., 2006,
Cat. J/A+A/451/881
27- 33 F7.5 deg RAdeg Right Ascension in decimal degrees (J2000)
35- 43 F9.5 deg DEdeg Declination in decimal degrees (J2000)
45- 49 F5.2 mag Rmag R band Vega magnitude
51- 55 F5.3 --- z Redshift (spectroscopic)
57- 59 F3.1 --- q_z Quality code for z (2=reliable) (1)
61 I1 --- Class [1/5] Spectroscopic classification code (2)
63- 88 A26 --- SWIRE SWIRE identification name,
SWIRE3_JHHMMSS.ss+DDMMSS.s (3)
90- 96 F7.4 [uJy] S3.6um ? Log of 3.6 micron band flux density
98-104 F7.4 [uJy] S24um ? Log of 24 micron band flux density
106-108 I3 --- XMMES1 ? XMM source name (4)
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Note (1): Quality code is numbered as:
2.0 = reliable, based on >2 confirmed lines
1.5 = very plausible, based on 2 lines
1.0 = uncertain
Note (2): Spectroscopic classification code as follows:
1 = type-1 AGN
2 = type-2 AGN
3 = Emission-Line Galaxy (ELG)
4 = normal galaxy
5 = star
Note (3): Of the most probable corresponding Spitzer source.
Contains in a few cases a number in place of the SWIRE identification,
not explained in the paper.
Note (4): see Feruglio et al., 2008, Cat. J/A+A/488/417.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 26-Jan-2010