J/AJ/159/43 Spectroscopically identified CVs from LAMOST survey. I. (Hou+, 2020)
Spectroscopically identified cataclysmic variables from the LAMOST survey.
I.The sample.
Hou W., Luo A.-L., Li Y.-B., Qin Li
<Astron. J., 159, 43 (2020)>
=2020AJ....159...43H 2020AJ....159...43H
ADC_Keywords: Stars, variable; Novae; Spectra, optical; Stars, Am
Keywords: Cataclysmic variable stars ; Dwarf novae ; Nova-like variable stars ;
Catalogs ; Astronomy data analysis
Abstract:
A sample of cataclysmic variables (CVs) is presented including
spectroscopically identified 380 spectra of 245 objects, of which 58
CV candidates are new discoveries. The BaggingTopPush and the Random
Forest algorithms are applied to the Fifth Data Release (DR5) of the
Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) to
retrieve CVs with strong emission lines and with broad absorption
lines respectively. Based on spectroscopic classification, 134 dwarf
novae, 41 nova-like variables, and 19 magnetic CVs are identified from
the sample. In addition, 89 high-inclination systems and 33 CVs
showing companion stars are recognized and discussed for their
distinct spectral characteristics. Comparisons between CVs from LAMOST
and from published catalogs are made in spatial and magnitude
distribution, and the difference of their locus in the Gaia
color-absolute magnitude diagram (CaMD) are also investigated. More
interestingly, for two dwarf novae observed through LAMOST and SDSS in
different epochs, their spectra both in quiescence phase and during
outburst are exhibited.
Description:
Using the rank-based algorithm in combination with the Random Forest
algorithm, we pick out 380 spectra of 245 cataclysmic variables (CVs)
from Large Sky Area Multi-Object Fiber Spectroscopic Telescope Data
Release 5 (LAMOST DR5), among which 71 spectra of 58 CVs are new
discoveries.
The LAMOST-I regular survey was defined as from 2012 September to 2017
June, which covers approximately 17000 square degrees of the sky. The
data of LAMOST-I survey together with the pilot survey make up the
DR5. LAMOST is able to acquire 4000 spectra simultaneously in a single
exposure with a limiting magnitude as faint as r∼18 at the resolution
of 1800. The wavelength range for these low resolution spectra covers
the optical band from 3700 to 9000Å.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 138 380 Catalog of cataclysmic variables (CVs) selected
from the Large Sky Area Multi-Object Fiber
Spectroscopic Telescope (LAMOST) Data Release 5
(DR5)
--------------------------------------------------------------------------------
See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2014)
B/gcvs : General Catalogue of Variable Stars (Samus+, 2017)
V/123 : Catalog of Cataclysmic Variables (Downes+ 2001-2006)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
J/ApJ/565/511 : Cataclysmic variables in the 2MASS 2IDR (Hoard+, 2002)
J/AJ/134/185 : Cataclysmic variables from SDSS-DR5 (Szkody+, 2007)
J/AJ/142/181 : CVs from SDSS. VIII. The final year (Szkody+, 2011)
J/AJ/144/81 : Spectrosc. & phot. of CV candidates (Thorstensen+, 2012)
J/MNRAS/421/2414 : Faint cataclysmic variables from SDSS (Woudt+, 2012)
J/MNRAS/443/3174 : 72 faint CV candidates in CRTS (Breedt+, 2014)
J/MNRAS/441/1186 : Cataclysmic variables from CRTS (Drake+, 2014)
J/AcA/65/313 : Thousand new dwarf novae from the OGLE Survey (Mroz+, 2015)
J/MNRAS/456/4441 : Outburst catalogue cataclysmic variables (Coppejans+, 2016)
J/MNRAS/465/4968 : Cataclysmic variables observations (Hardy+, 2017)
J/other/RAA/18.68 : Cataclysmic variables from LAMOST DR3 (Han+, 2018)
J/ApJS/234/31 : Carbon stars from LAMOST using machine learning (Li+, 2018)
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 A1 --- f_LAMOST [*] Flag on LAMOST, indicate the newly
discovered CV spectra (71 occurrences)
3- 22 A20 --- LAMOST LAMOST designation (JHHMMSS.ss+DDMMSS.s)
24- 52 A29 --- OName ? Previous identifications of known CVs
54- 64 F11.7 deg RAdeg [3/356] Right Ascension (J2000)
66- 75 F10.7 deg DEdeg [-8.6/58.1] Declination (J2000)
77- 81 I5 d MJD [55859/57912] Local modified Julian Date of
observation, (JD-2400000.5)
83- 94 A12 --- Type Subtypes of CVs (1)
96-113 A18 --- Type-lit Literature subtypes of CVs
115-115 A1 --- CN [y/n] CIII/NIII emission line detection; y=yes
(119 occurrences), n=no (261 occurrences)
117-117 A1 --- FeII [y/n] Fe II emission line detection; y=yes
(127 occurrences), n=no (253 occurrences)
119-119 A1 --- Ha [S/D] S=Single-peak (291 occurrences) or
D=Double-peak (89 occurrences) Hα line
121-129 F9.3 --- Hb/HeII [-9999.0/9999.0] Ratio, Hβ/HeII 4686A (2)
131-138 F8.2 --- HeII/Hb [-9999.0/9999.0] Ratio, HeII 4686A/Hβ (2)
--------------------------------------------------------------------------------
Note (1): Types as follows:
CV = cataclysmic variables (186 occurrences)
DN = dwarf novae (109 occurrences)
DN_burst = dwarf novae burst (25 occurrences)
MCV = AM CVn type stars (19 occurrences)
NL-candidate = nova-like candidate (41 occurrences)
Note (2): Values of these two ratios might be set to 0, 9999 or -9999 in some
cases.
-9999 = Hβ line(s) appears in absorption; no HeII emission
line(s) detected;
0 (Hb/HeII) = Hβ lines appear in absorption; HeII in emission;
0 (HeII/Hb) = HeII not detected; Hβ lines in emission;
9999 (Hb/HeII) = HeII not detected; Hβ lines in emission;
9999 (HeII/Hb) = Hβ lines appear in absorption; HeII in emission;
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 25-Mar-2020