J/ApJ/910/120 Dwarf nova outbursts detected by ASAS-SN (Kawash+, 2021)
Classical novae masquerading as dwarf novae? Outburst properties of cataclysmic
variables with ASAS-SN.
Kawash A., Chomiuk L., Strader J., Aydi E., Sokolovsky K.V., Jayasinghe T.,
Kochanek C.S., Schmeer P., Stanek K.Z., Mukai K., Shappee B., Way Z.,
Basinger C., Holoien T.W.-S., Prieto J.L.
<Astrophys. J., 910, 120 (2021)>
=2021ApJ...910..120K 2021ApJ...910..120K
ADC_Keywords: Novae; Photometry, UBV; Surveys; Stars, variable
Keywords: Classical novae ; Dwarf novae ; Cataclysmic variable stars ;
Novae ; White dwarf stars
Abstract:
The unprecedented sky coverage and observing cadence of the All-Sky
Automated Survey for SuperNovae (ASAS-SN) has resulted in the
discovery and continued monitoring of a large sample of Galactic
transients. The vast majority of these are accretion-powered dwarf
nova outbursts in cataclysmic variable systems, but a small subset are
thermonuclear-powered classical novae. Despite improved monitoring of
the Galaxy for novae from ASAS-SN and other surveys, the observed
Galactic nova rate is still lower than predictions. One way classical
novae could be missed is if they are confused with the much larger
population of dwarf novae. Here, we examine the properties of 1617
dwarf nova outbursts detected by ASAS-SN and compare them to classical
novae. We find that the mean classical nova brightens by ∼11mag during
outburst, while the mean dwarf nova brightens by only ∼5mag, with the
outburst amplitude distributions overlapping by roughly 15%. For the
first time, we show that the amplitude of an outburst and the time it
takes to decline by two magnitudes from maximum are positively
correlated for dwarf nova outbursts. For classical novae, we find that
these quantities are negatively correlated, but only weakly, compared
to the strong anticorrelation of these quantities found in some
previous work. We show that, even if located at large distances, only
a small number of putative dwarf novae could be misclassified as
classical novae, suggesting that there is minimal confusion between
these populations. Future spectroscopic follow-up of these candidates
can show whether any are indeed classical novae.
Description:
The list of cataclysmic variables (CVs) analyzed in this work was
obtained from the AAVSO International Variable Star Index (VSX;
Watson+ 2006, B/vsx).
Image-subtraction light curves were generated using ASAS-SN
observations for all objects in our sample. ASAS-SN light curves for
most fields outside of the Galactic plane span back to 2013.
See Section 2.2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 82 1617 Outburst properties of dwarf novae
table2.dat 84 8 Classical and rapid recurrent nova candidates
table3.dat 67 40 Outburst properties of classical and recurrent novae
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
I/305 : The Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
II/366 : ASAS-SN catalog of variable stars (Jayasinghe+, 2018-2020)
I/353 : The Guide Star Catalog, Version 2.4.2 (GSC2.4.2) (STScI, 2020)
J/ApJS/187/275 : Photometric histories of recurrent novae (Schaefer, 2010)
J/AJ/140/34 : Classification of nova light curves (Strope+, 2010)
J/PASJ/64/63 : Dwarf novae characterization using SDSS colors (Kato+, 2012)
J/MNRAS/441/1186 : Cataclysmic variables from CRTS (Drake+, 2014)
J/ApJ/788/164 : Known Galactic classical novae data (Pagnotta+, 2014)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/AcA/65/313 : One thousand new dwarf novae from OGLE Survey (Mroz+, 2015)
J/MNRAS/456/4441 : Outburst catalog of cataclysmic variables (Coppejans+, 2016)
J/ApJ/833/149 : Opt/NIR obs. of M31N 2008-12a 2015 eruption (Darnley+, 2016)
J/MNRAS/460/2526 : Dwarf novae outbursts properties (Otulakowska-Hypka+, 2016)
J/ApJ/834/196 : Galactic novae with m≤10 from 1900 to 2015 (Shafter, 2017)
J/MNRAS/491/655 : Photometry and spectroscopy of RN LMC 1968 (Kuin+, 2020)
http://asd.gsfc.nasa.gov/Koji.Mukai/novae/novae.html : List of Gal. novae
http://www.astronomy.ohio-state.edu/asassn/ : ASAS-SN home page
http://www.aavso.org/ : AAVSO home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 28 A28 --- Name Dwarf Novae Name
30- 31 I2 h RAh Hour of Right Ascension (J2000)
33- 34 I2 min RAm Minute of Right Ascension (J2000)
36- 40 F5.2 s RAs Second of Right Ascension (J2000)
42- 42 A1 --- DE- Sign of the Declination (J2000)
43- 44 I2 deg DEd Degree of Declination (J2000)
46- 47 I2 arcmin DEm Arcminute of Declination (J2000)
49- 52 F4.1 arcsec DEs Arcsecond of Declination (J2000)
54- 57 F4.1 mag Peak [10/16.6] Peak apparent brightness
59- 61 F3.1 mag Amp [0.9/9.7] Amplitude of outburst
63- 63 I1 --- f_Amp [0/1]? Amplitude flag (G1)
65- 69 F5.1 d t2 [0.7/211.4] Decline time (G2)
71- 71 I1 --- f_t2 [0/1]? Flag on t2 (G3)
73- 76 F4.1 d b_t2 [0/71]? Lower bound on t2 (G4)
78- 82 F5.1 d B_t2 [0.9/212] Upper bound on t2 (G4)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Dwarf Novae Name
13- 14 I2 h RAh [9/18] Hour of Right Ascension (J2000)
16- 17 I2 min RAm Minute of Right Ascension (J2000)
19- 23 F5.2 s RAs Second of Right Ascension (J2000)
25- 25 A1 --- DE- [-] Sign of the Declination (J2000)
26- 27 I2 deg DEd [9/59] Degree of Declination (J2000)
29- 30 I2 arcmin DEm Arcminute of Declination (J2000)
32- 35 F4.1 arcsec DEs Arcsecond of Declination (J2000)
37- 43 F7.3 deg GLON Galactic longitude
45- 50 F6.3 deg GLAT Galactic latitude
52- 55 F4.1 mag Peak [13.5/16.3] Peak g-band apparent brightness
57- 57 A1 --- l_Amp Limit flag on Amp
59- 61 F3.1 mag Amp [6.5/8.2]? Amplitude of outburst
63- 66 F4.1 d b_t2 [5.9/14.2]? Lower bound on t2
68- 71 F4.1 d B_t2 [7.9/32.9] Upper bound on t2
73- 76 F4.1 mag Ag [1.4/19.8] Extinction at g-band (1)
78- 78 A1 --- l_tauR Limit flag on tauR
80- 82 F3.1 yr tauR [0.8/4.0] Outburst recurrence time
84- 84 A1 --- 10kpc [YN] As close as 10 kpc?
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Note (1): g-band extinction from Schlafly & Finkbeiner (2011ApJ...737..103S 2011ApJ...737..103S)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Dwarf Novae Name
11- 12 I2 h RAh Hour of Right Ascension (J2000)
14- 15 I2 min RAm Minute of Right Ascension (J2000)
17- 21 F5.2 s RAs Second of Right Ascension (J2000)
23- 23 A1 --- DE- Sign of the Declination (J2000)
24- 25 I2 deg DEd Degree of Declination (J2000)
27- 28 I2 arcmin DEm Arcminute of Declination (J2000)
30- 33 F4.1 arcsec DEs Arcsecond of Declination (J2000)
35- 38 F4.1 mag Peak [4.4/16.8] Peak apparent brightness
40- 43 F4.1 mag Amp [5.8/14.4] Amplitude of outburst
45- 45 I1 --- f_Amp [0/1]? Amplitude flag (G1)
47- 51 F5.1 d t2 [3.0/118.3] Decline time (G2)
53- 53 I1 --- f_t2 [0/1]? Flag on t2 (G3)
55- 59 F5.1 d b_t2 [1/114.7]? Lower bound on t2 (G4)
61- 65 F5.1 d B_t2 [3.1/118.3] Upper bound on t2 (G4)
67- 67 A1 --- Flag Flag (1)
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Note (1):
a = V0670 Ser: The eruption likely occurred during solar
constraint and B_t2 is the time from before solar constraint to once
the light curve dropped below the apparent two magnitude threshold.
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Global notes:
Note (G1): Amplitude flag as follows:
1 = outburst amplitude;
0 = lower limit.
Note (G2): The decline time, t2, defined as the time in days it takes for the
light curve to decline by two magnitudes from maximum brightness.
Note (G3): t2 flag as follows:
1 = object detected below the two magnitude threshold;
0 = only a non-detection below this threshold; the t2 value listed is
likely larger than the true value.
Note (G4): The b_t2 column gives the time until last detection above the two
magnitude threshold and the B_t2 column gives the time until the first
detection or non-detection below this threshold.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 12-Sep-2022