Quality Flags, Redshifts and Spectral Features

From VVDS "flags" page, author Laurence Tresse
Edited by BG, 1/10/2009



1. SUMMARY FILES
   1.1. SUMMARY : VVDS-FLAGS AND CONFIDENCE CLASSES

Flags should be assigned according to the following table

Confidence in redshift      Primary      Targets       Secondary Identified Objects Secondary Non-Identified Objects Primary QSO Targets (a) Secondary QSO Identified Objects Secondary QSO Non-Identified Objects Primary Problematic Targets (b)     Double Objects     (c) Fake(d) Detections
No redshift could be assigned 0
z = 9.9999
20
z = 9.9999
-20
z = 9.9999
- - - -10
z = 9.9999
-11
z = x.xxxx

-99
z = 9.9999
confidence 50%
(tentative z)
1 21 -21 11
may-be-qso
211 -211 - - -
confidence 75% 2 22 -22 12
may-be-qso but secure z
212 -212 - - -
confidence
95%
3 23 -23 13 213 -213 - - -
confidence
100%
4 24 -24 14 214 -213 - - -
Single, secure, isolated emission line(e) 9 29 -29 19 219 -219 - - -
Secondary means that it is not the object targeted from the ADP selection. (Note that the centroid of a secondary object has a great chance not to be centred within the slit, and thus there is a loss in flux).
Identified means correct ID + I(AB) filled in the summary.
Non-Identified means ID and I(AB) set to zeros in the summary.

a
Examples of VVDS QSOs Flags (courtesy IG)
b
Include the cases where the extracted target is a fake detection or a border object, while the target is visible in the 2D spectrum but has not been extracted. Do not extract objects manually!
c
The spectrum is a blend of 2 objects, as visible either from the obejct extraction profile, or from emission lines misplaced wrt the continuum, or from 2 different systems of emission lines giving discordant redshifts. Flag -11 identifies these cases as "double objects". If a redshift can be measured, do measure it, otherwise put 9.9999, but in any case flag the object as -11 (new flag!). Do write in the comments anything you think can be useful in a second phase. At some point, somebody will go through all flag -11 and disentangle the various cases (spectra can be separated or not, photometry is deblended or not, etc).
d It includes on-edge detections at the start or the end of the slit (i.e. in the spatial direction) even though it may be a real object because the shape of the extracted 1D spectrum is usually wrong in this case.
e
line should be one of Ha, [OII], [Hb], [OIIIa]

SPECIAL REMARK When the extracted object is NOT the target, DO NOT CHANGE THE ID OF THE TARGET, put flag -10 instead (case b of above table). If 2 or more objects are extracted, and NONE of them is the target, identify as secondary the one with the nicest spectrum, and leave the ID of the target unchanged with flag -10


   1.2. SUMMARY : REDSHIFTS
Redshifts in sumary files shall comply to the following rules


   1.3 SUMMARY : COMMENTS

For each object, please write comments to help other people understand why you put such a redshift/flag. Tipycally, the list of lines onto which the redshift was based should be there, plus other usefull informations, as in the examples below

2. EXEMPLES AND REFERENCES OF SPECTRA

- Stellar Spectra
Pickles,1985,ApJSS,59,33 is a good reference for a display of set of various stellar spectra.
- VVDS spectra
Combined VVDS spectra
- Galaxy Spectra
Kennicutt, ApJSS, 79,1992 is a good reference for a display of set of various galaxy spectra.
plot1 UV data in the Storchi-Bergmann, Calzetti & Kinney compilation
plot2 UV data in the Storchi-Bergmann, Calzetti & Kinney compilation
- QSO Spectra
Examples from literature
Examples of VVDS QSOs
- Faint blue galaxy templates [1500-3000 Angs]
examples that is for galaxies at 1.4 <z< 3.5
- Spectra with Lyman_alpha [1000-1800 Angs]
2 plots with W(Lya)<-7Ang and -7<W(Lya)<7Ang from Steidel et al. 2004
2 plots with 7<W(Lya)<20Ang and W(Lya)>20Ang from Steidel et al. 2004
1 plot W(Lya)>0Ang from Shaple, Steidel, Pettini & Adelberger, 2003, in press (astro-ph/0301230)


3. SPECTRAL LINES
Below, the list of lines as known by VIPGI. Such list is in file "lines.dat", in the config directory under the VIPGI INSTALLATION tree. If wished you can edit (carefully) such file. In the following table, conventions are as follows
- When it is a doublet, then both lines should be observed.
- In red are the main lines for galaxies.
- A : Lines only in absorption, E : Lines only in emission, AE : Lines either in emission or in absorption.
- B : Main broad lines seen in AGN.

Lambda Label Lines
10320 [10320] E [SII]
9381 [9381.0] A CN
9190 [9190.0] A CN
8863 [8863.0] A TiO (stellar)
8542 [8542.0] A CaII
8430 [8430.0] A TiO (stellar)
8195 [8195.0] A NaI
8183 [8183.0] A NaI
7590 [7590.0] A TiO (stellar)
7325 [7325.0] E [OII]7319.0+7330.3
7136 [7135.8] E [ArIII]
7065 [7065.2] AE HeI
6725 [6725.0] E [SII]6717.0+6731.3
6678 [6678.1] AE HeI
6584 [6583.6] E [NII] (doublet-1)
6563 [6562.8] AE, B Halpha
6548 [6548.1] E [NII] (doublet-1/3)
6364 [6363.9] E [OI] (doublet-1)
6300 [6300.2] E [OI] (doublet-2)
6159 [6159.0] A TiO (stellar)
5893 [5892.5] A NaD
5876 [5875.6] AE HeI
5615 [5615.0] A FeI
5603 [5603.0] A TiO (stellar)
5411 [5411.0] AE HeII
5324 [5324.0] A FeI
5269 [5269.0] A Ca, Fe
5232 [5232.0] A FeI
5175 [5175.4] A MgI
5007 [5006.8] E [OIII] (doublet-1)
4959 [4958.9] E [OIII] (doublet-1/3)
4861 [4861.3] AE, B Hbeta
4686 [4685.7] AE HeII
4471 [4471.6] AE HeI
4466 [4466.0] A FeI
4384 [4383.6] A FeI
4363 [4363.2] E [OIII]
4340 [4340.4] AE Hgamma
4304 [4304.4] A Gband
4271 [4271.0] A FeI
4260 [4260.0] A FeI
4227 [4226.7] A CaI, FeI
4216 [4216.0] A CN
4102 [4101.7] AE Hdelta
4000 [4000.0] Break Balmer break
4072 [4072.0] E [SII]4068.6+4076.2
4045 [4045.0] A FeI
3968 [3967.5] E [NeIII] (doublet-1)
3970 [3970.1] AE Hepsilon
3969 [3968.5] A CaII H
3934 [3933.7] A CaII K
3889 [3889.1] AE Hksi, CN (H8)
3889 [3888.8] AE HeI
3869 [3868.7] E [NeIII] (doublet-2)
3835 [3835.4] A FeI, H9(AE)
3818 [3818.0] A FeI
3798 [3797.9] AE Hteta
3771 [3770.6] AE H11
3734 [3734.4] A FeI, H13(AE)
3727 [3727.5] E [OII]
3722 [3722.0] AE H14
3581 [3581.0] A FeI
3426 [3425.8] E [NeV] (doublet-1)
3346 [3345.9] E [NeV] (doublet-2)
3191 [3191.0] E FeII
3134 [3134.0] E [OIII]
2964 [2964.0] E FeII, Broad bump in AGN
2853 [2852.9] A MgI
2799 [2799.0] AE, B MgII
2626 [2626.0] E FeII
2600 [2600.0] A FeII
2586 [2586.7] A FeII
2424 [2424.0] E [NeIV]
2382 [2382.0] A FeII
2374 [2374.0] A FeII
2344 [2344.2] A FeII
2326 [2326.0] E CII, FeII
2260 [2260.0] A FeII
2142 [2142.0] E [NII]
2077 [2077.0] A FeIII
1909 [1909.0] E, B [CIII]
1856 [1856.0] A AlIII
1671 [1670.8] A AlII
1640 [1640.0] AE HeII
1608 [1608.5] A FeII
1549 [1549.0] AE, B CIV 1548+1550
1527 [1526.7] A SiII
1397 [1397.0] AE, B SiIV 1393 + OIV 1402
1334 [1334.5] A CII
1303 [1303.0] A [OI]1302+1304
1260 [1260.4] A SiII
1240 [1240.0] AE NV
1216 [1215.7] AE, B LyA
1033 [1033.0] AE OVI
1026 [1025.6] AE LyB
973 [ 972.5] AE LyG