J/A+A/379/798 ELAIS Hα emitting galaxies (Pascual+, 2001)
Hα emitting galaxies and the star formation rate density at z ≃ 0.24.
Pascual S., Gallego J., Aragon-Salamanca A., Zamorano J.
<Astron. Astrophys. 379, 798 (2001)>
=2001A&A...379..798P 2001A&A...379..798P
ADC_Keywords: Galaxies, photometry ; Equivalent widths
Keywords: galaxies: distances and redshifts - galaxies: evolution -
galaxies: luminosity function, mass function
Abstract:
We have carried out a survey searching for Hα emitting galaxies
at z∼0.24 using a narrow band filter tuned with the redshifted line.
The total sky area covered was 0.19 square degrees within the redshift
range 0.228 to 0.255 in a set of four fields in the ELAIS-N1 zone.
This corresponds to a volume of 9.8x103Mpc3 and a look-back time
of 3.6Gyr when H=50km/s/Mpc and q=0.5 are assumed. A total of 52
objects are selected as candidates for a broad band limiting magnitude
of I∼22.9, plus 16 detected only in the narrow band image for a narrow
band limiting magnitude for object detection of 21.0. The threshold
detection corresponds to about 20Å equivalent width with an
uncertainty of ~±10Å. Point-like objects (15) were excluded from
our analysis using CLASS_STAR parameter from SExtractor. The
contamination from other emission lines such as [O II]λ3727,
Hβ and [OIII]λλ4959,5007 at redshifts 1.2, 0.66 and
0.61 respectively is estimated, and found to be negligible at the flux
limits of our sample. We find an extinction-corrected Hα
luminosity density of (5.4±1.1)x1039erg/s/Mpc3.
Our survey for Hα emitting galaxies was carried out using the
focal reducer CAFOS at the 2.2 m telescope in CAHA (Centro Astronomico
Hispano-Aleman, Almeria, Spain). This instrument is equipped with a
2048x2048 Site#1d CCD with 24µm pixels (0.53" on the sky), which
covers a circular area of 16'diameter.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 66 69 Objects selected in the fields ELAIS a3, a4, b3
and b4 with measurements.
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See also:
J/MNRAS/302/222 : ISO ELAIS 20cm VLA survey regions (Ciliegi+, 1999)
J/MNRAS/305/297 : ISO ELAIS 1.4GHz survey (Gruppioni+, 1999)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Field ELAIS field name (1)
4- 8 I5 --- ID Identification number in the ELAIS field (1)
9 A1 --- n_ID [ab] Note on ID (2)
11- 12 I2 h RAh Right ascension (J2000)
14- 15 I2 min RAm Right ascension (J2000)
17- 20 F4.1 s RAs Right ascension (J2000)
22 A1 --- DE- Declination sign (J2000)
23- 24 I2 deg DEd Declination (J2000)
26- 27 I2 arcmin DEm Declination (J2000)
29- 33 F5.2 arcsec DEs Declination (J2000)
35 A1 --- l_Imag Limit flag on Imag
36- 39 F4.1 mag Imag I Cousins magnitude
42- 45 F4.1 mag Hamag Hα narrow band (816nm) magnitude
47 A1 --- l_EWHa Limit flag on EWHa
48- 51 I4 0.1nm EWHa Hα equivalent width
53- 56 F4.1 --- sigma sigma excess of the detection
58- 61 F4.2 --- IClass CLASS_STAR parameter produced by SExtractor
in Cousins I band image (3)
63- 66 F4.2 --- HaClass CLASS_STAR parameter produced by SExtractor
in Hα narrow band image (3)
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Note (1): Identified as [PGA2001] ELAIS aN NNNNN in Simbad
a3_551 and a4_10732 are the same object.
Note (2): a: Selected under the broad limit magnitude
b: Catalogued as star
Note (3): SExtractor CLASS_STAR parameter:
0 = galaxy
1 = star
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History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 29-Jan-2002