J/ApJS/155/271 Chandra Deep Field-South: Optical spectroscopy (Szokoly+, 2004)
The Chandra Deep Field-South: Optical spectroscopy. I..
Szokoly G.P., Bergeron J., Hasinger G., Lehmann I., Kewley L., Mainieri V.,
Nonino M., Rosati P., Giacconi R., Gilli R., Gilmozzi R., Norman C.,
Romaniello M., Schreier E., Tozzi P., Wang J.X., Zheng W., Zirm A.
<Astrophys. J. Suppl. Ser., 155, 271-349 (2004)>
=2004ApJS..155..271S 2004ApJS..155..271S
ADC_Keywords: X-ray sources ; Surveys ; Photometry ; Redshifts
Keywords: cosmology: observations - galaxies: active - quasars: general -
surveys - techniques: spectroscopic - X-rays: galaxies: clusters
Abstract:
We present the results of our spectroscopic follow-up program of the
X-ray sources detected in the 942ks exposure of the Chandra Deep
Field-South (CDFS). A total of 288 possible counterparts were observed
at the VLT with the FORS1/FORS2 spectrographs for 251 of the 349
Chandra sources (including three additional faint X-ray sources).
Spectra and R-band images are shown for all the observed sources and
R-K colors are given for most of them. Spectroscopic redshifts were
obtained for 168 X-ray sources, of which 137 have both reliable
optical identification and redshift estimate (including 16 external
identifications). The R<24 observed sample comprises 161 X-ray objects
(181 optical counterparts), and 126 of them have unambiguous
spectroscopic identification.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 161 390 Optical spectroscopy results
table5.dat 115 3 X-Ray sources not yet published in Giacconi
et al., 2002, Cat. J/ApJS/139/369
table8.dat 53 139 Optical counterparts not observed in our program
table9.dat 95 130 Optical spectroscopy results for field galaxies
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See also:
J/ApJS/139/369 : Chandra Deep Field South. 1 Ms catalog (Giacconi+, 2002)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- EName ? Extended source name
5 A1 --- f_EName [wn] Source association (1)
7- 9 I3 --- [GZW2002] Unique Detection identification number,
[GZW2002] XID NNN in Simbad (G1) (2)
10 A1 --- m_[GZW2002] [a-e] Multiplicity index on [GZW2002] (G1)
11 A1 --- n_[GZW2002] [*] *: Extended X-ray objects
13- 23 A11 --- Mask Mask designations
25- 26 I2 h RAh Hour of Right Ascension (J2000) (3)
28- 29 I2 min RAm Minute of Right Ascension (J2000) (3)
31- 35 F5.2 s RAs Second of Right Ascension (J2000) (3)
37 A1 --- DE- Sign of the Declination (J2000) (3)
38- 39 I2 deg DEd Degree of Declination (J2000) (3)
41- 42 I2 arcmin DEm Arcminute of Declination (J2000) (3)
44- 47 F4.1 arcsec DEs Arcsecond of Declination (J2000) (3)
49- 53 F5.2 mag Rmag ? The R band magnitude (Vega)
54 A1 --- f_Rmag [XW-] Flag on Rmag (G2)
56 A1 --- l_R-K Limit flag on R-K
57- 61 F5.2 mag R-K ? The (R-K) color (Vega)
62- 63 A2 --- f_R-K Flag on R-K (G3)
65- 68 F4.1 [10-7W] logLX ? Log base 10 of the 0.5-10keV luminosity (4)
70- 74 F5.2 --- HR Hardness ratio (G4)
76- 80 F5.3 --- z ? Best redshift estimate (5)
82- 87 A6 --- OClass Optical classification (6)
89- 97 A9 --- XClass X-ray classification (7)
99-101 F3.1 --- Qual Redshift reliability determination (8)
102 A1 --- f_Qual [+] +: we consider the identification final
for the X-ray source
104-161 A58 --- Comm Additional comments (9)
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Note (1):
w = with associated point source
n = no associated point source
Note (2): When an object was observed repeatedly,
multiple entries are given in the table.
Note (3): Coordinates of the optical object, not those of the X-ray source.
Astrometry is based on the USNO (Monet et al. 1998) reference frame,
just like the X-ray positions in Giacconi et al. (2002, Cat.
J/ApJS/139/369) and the astrometric accuracy is better than 0.2".
Note (4): Assuming an Ωm=0.3, ΩΛ=0.7 universe.
Note (5): The selected low spectral resolution leads to an uncertainty
in the redshift determination of ±0.005. For broad emission line
objects the uncertainty is significantly higher. The quoted redshift
value always refers to the particular observation of the object, thus,
there can be slight discrepancies between observations of the same
object or missing redshift values for some masks.
Note (6): Optical classification is defined as follows:
BLAGN = Objects with emission lines broader than 2000km/s. This
classification implies an optical type 1 AGN or QSO.
HEX = Object with unresolved emission lines and exhibiting high
ionization lines or emission line ratios indicating AGN
activity. These objects are dominantly optical type 2 AGNs
or QSOs, but in a few cases the optical type 1/2
distinction is not possible based on the data.
LEX = Objects with unresolved emission lines consistent with an
H II region-type spectra. These objects would be classified
as normal galaxies based on the optical data alone as the
presence of the AGN cannot be established.
ABS = A typical galaxy spectrum showing only absorption lines
BLLAC? = May be a BL Lac object
M-star = M-type star
star = A stellar spectrum
Note (7): X-ray classification is defined as follows:
AGN-1 = 1042erg/s≤LX(0.5-10keV)<1044erg/s and HR≤-0.2
AGN-2 = 1041erg/s≤LX(0.5-10keV)<1044erg/s (lower limit smaller
than for the AGN-1 population to account for substantial
absorption) and HR>-0.2.
QSO-1 = LX(0.5-10keV)≥1044erg/s and HR≤-0.2
QSO-2 = LX(0.5-10keV)≥1044erg/s and HR>-0.2
gal = LX(0.5-10keV)≤1042erg/s and HR←0.2 or
LX(0.5-10keV)≤10^41rg/s (any HR)
star = This class is defined from the optical spectra and/or proper motions
M-star = M-type star
Note (8): Quality flags as follows:
2.0 = reliable redshift determination,
1.0 = we clearly detect some feature (typically a single narrow
emission line) in the spectrum that cannot be identified securely.
0.0 = no success,
0.5 = there is a hint of some spectral feature. This quality flag
only refers to the reliability of the spectroscopic classification.
Note (9): See Table 6 for diagnostics on line ratios.
ref 1 = A. Cimatti & R. Gilli, private communication,
ref 2 = paper I: Giacconi et al., 2001ApJ...551..624G 2001ApJ...551..624G
ref 3 = C. Wolf, private communication;
ref 4 = Daddi et al. (2004ApJ...600L.127D 2004ApJ...600L.127D)
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [GZW2002] Unique Detection identification number,
[GZW2002] XID NNN in Simbad
5- 20 A16 --- CXO CXO designation (JHHMMSS.s-DDMMSS)
22- 23 I2 h RAh Right ascension (J2000.0)
25- 26 I2 min RAm Right ascension (J2000.0)
28- 32 F5.2 s RAs Right ascension (J2000.0)
34 A1 --- DE- Declination sign (J2000.0)
35- 36 I2 deg DEd Declination (J2000.0)
38- 39 I2 arcmin DEm Declination (J2000.0)
41- 45 F5.2 arcsec DEs Declination (J2000.0)
47 A1 --- l_SCts Limit flag on S
48- 51 F4.1 ct SCts Net counts in soft (0.5-2keV) band
53- 56 F4.1 ct e_SCts ? rms uncertainty on S
58 A1 --- l_HCts Limit flag on H
59- 62 F4.1 ct HCts Net counts in hard (2-10keV) band
64- 66 F3.1 ct e_HCts ? rms uncertainty on H
68- 72 F5.1 ks STime Effective exposure time in the soft band
74- 78 F5.1 ks HTime Effective exposure time in the soft band
80 A1 --- l_SFlux Limit flag on FS
81- 87 E7.1 mW/m2 SFlux Flux in soft band
89- 95 E7.1 mW/m2 e_SFlux ? rms uncertainty on FS
97 A1 --- l_HFlux Limit flag on FH
98-104 E7.1 mW/m2 HFlux Flux in hard band
106-112 E7.1 mW/m2 e_HFlux ? rms uncertainty on FH
114-115 I2 --- HR Hardness ratio, (H-S)/(H+S) (G4)
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1 I1 --- Type [1/4] Counterpart type code (1)
3- 5 I3 --- [GZW2002] Unique Detection identification number,
[GZW2002] XID NNN in Simbad (G1)
6 A1 --- m_[GZW2002] [a-e] Multiplicity index on [GZW2002] (G1)
7 A1 --- n_[GZW2002] [*] *: Extended X-ray object
9- 10 I2 h RAh Hour of Right Ascension (J2000) (2)
12- 13 I2 min RAm Minute of Right Ascension (J2000) (2)
15- 19 F5.2 s RAs Second of Right Ascension (J2000) (2)
21 A1 --- DE- Sign of the Declination (J2000) (2)
22- 23 I2 deg DEd Degree of Declination (J2000) (2)
25- 26 I2 arcmin DEm Arcminute of Declination (J2000) (2)
28- 32 F5.2 arcsec DEs Arcsecond of Declination (J2000) (2)
34- 38 F5.2 mag Rmag ? The R band magnitude (Vega)
39 A1 --- f_Rmag [W] Flag on Rmag (G2)
41- 45 F5.2 mag R-K ? The (R-K) band color (Vega)
46- 47 A2 --- f_R-K [K - NA] Flag on R-K (G3)
49- 53 F5.2 --- HR Hardness ratio (G4)
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Note (1): Counterpart type coded as follows:
1 = Additional counterpart candidates;
2 = Inside the 8arcmin circle;
3 = Outside the 8arcmin circle;
4 = Objects not covered by our imaging survey.
Note (2): Coordinates of the optical object, not those of the X-ray source.
Astrometry is based on the USNO (Monet et al., 1998, Cat. I/252)
reference frame, just like the X-ray positions in Giacconi et al.
(2002, Cat. J/ApJS/139/369) and the astrometric accuracy is better
than 0.2 arcsec.
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq Sequential number
7- 17 A11 --- Mask Mask designations
19- 20 I2 h RAh Hour of Right Ascension (J2000)
22- 23 I2 min RAm Minute of Right Ascension (J2000)
25- 29 F5.2 s RAs Second of Right Ascension (J2000)
31 A1 --- DE- Sign of the Declination (J2000)
32- 33 I2 deg DEd Degree of Declination (J2000)
35- 36 I2 arcmin DEm Arcminute of Declination (J2000)
38- 41 F4.1 arcsec DEs Arcsecond of Declination (J2000)
43- 47 F5.2 mag Rmag ? The R band magnitude (Vega)
48- 49 A2 --- f_Rmag [NA ] NA: No data to determine magnitude
51- 55 F5.3 --- z Best redshift estimate (1)
57- 62 A6 --- Class Classification (2)
64 I1 --- Qual [1/2]? Redshift reliability determination (3)
66- 94 A29 --- Comm Additional comments
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Note (1): The selected low spectral resolution leads to an uncertainty
in the redshift determination of ±0.005. For broad emission line
objects the uncertainty is significantly higher. The quoted redshift
value always refers to the particular observation of the object, thus,
there can be slight discrepancies between observations of the same
object or missing redshift values for some masks.
Note (2): Classification as follows:
BLAGN = Objects with emission lines broader than 2000km/s.
This classification implies an optical type 1 AGN or QSO.
M-star = M-type star
NELG = Narrow Emission Line Galaxies
gal = galaxy
star = star
Note (3): Quality flag defined as follows:
2 = a reliable redshift determination.
1 = that we clearly detect some feature (typically a single narrow
emission line) in the spectrum that cannot be identified securely.
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Global notes:
Note (G1): This is the unique detection ID (XID) in the published catalog
(Giacconi et al., 2002, Cat. J/ApJS/139/369). In cases of multiple
counterparts, a letter is appended to this number to distinguish
between the optical candidates.
Note (G2): Flag on Rmag means the following:
X = very bright star. External magnitude from USNO;
- = data is too faint to be useful;
W = the WFI magnitude (Giacconi et al., 2002, Cat. J/ApJS/139/369)
for objects not covered by our FORS imaging survey.
Note (G3): Flags on R-K means the following:
- = data is to faint to be useful;
NA = limited near-infrared coverage;
K = the K band magnitude (Vega) instead of the R-K color;
M = 2MASS magnitude is used for the K-band.
Note (G4): HR=(H-S)/(H+S), where H and S are the net count rates in the
hard (2-10keV) and soft (0.5-2keV) band, respectively. It is important
to point out that the hardness ratio is defined in instrument counts
(for Chandra ACIS-I), thus for different X-ray telescopes or
instruments, it should be converted using their specific energy
conversion factors.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 28-Jun-2005