J/ApJ/793/134 M33 SNR candidates properties (Lee+, 2014)
Properties of optically selected supernova remnant candidates in M33.
Lee J.H., Lee M.G.
<Astrophys. J., 793, 134 (2014)>
=2014ApJ...793..134L 2014ApJ...793..134L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Supernova remnants ; Stars, diameters ;
Photometry, H-alpha
Keywords: galaxies: individual: M33 - galaxies: ISM - ISM: supernova remnants
Abstract:
Narrowband images covering strong emission lines are efficient for
surveying supernova remnants (SNRs) in nearby galaxies. Using the
narrowband images provided by the Local Group Galaxy Survey, we
searched for SNRs in M33. Culling the objects with enhanced
[S II]/Hα and round morphology in the continuum-subtracted
Hα and [S II] images, we produced a list of 199 sources. Among
them, 79 are previously unknown. Their progenitor and morphology types
were classified. A majority of the sample (170 objects) are likely
remnants of core-collapse supernovae (SNe), and 29 are remnants of
Type Ia SNe. The cumulative size distribution of these objects is
found to be similar to that of the M31 remnants derived in a similar
way. We obtain a power-law slope, α=2.38±0.05. Thus, a
majority of the sources are considered to be in the Sedov-Taylor
phase, consistent with previous findings. The histogram of the
emission-line ratio ([S II]/Hα) of the remnants has two
concentrations at [S II]/Hα ∼0.55 and ∼0.8, as in M31.
Interestingly, LX(and L_20 cm_) of the compact center-bright objects
are correlated with their optical luminosity. The remnants with X-ray
emission have brighter optical surface brightnesses and smaller
diameters than those without X-ray emission.
Description:
We utilized the Hα and [S II] images in the LGGS to find new M33
remnants. The LGGS covered three 36' square fields of M33. We
subtracted continuum sources from the narrowband images using R-band
images. We smoothed the images with better seeing to match the
point-spread function in the images with worse seeing, using the IRAF
task psfmatch. We then scaled and subtracted the resulting continuum
images from narrowband images. We selected M33 remnants considering
three criteria: emission-line ratio ([S II]/Hα), the morphological
structure, and the absence of blue stars inside the sources. Details
are described in L14 (Lee et al. 2014ApJ...786..130L 2014ApJ...786..130L). We detected
objects with [S II]/Hα>0.4 in emission-line ratio maps, and
selected objects with round or shell structures in each narrowband
image. As a result, we chose 435 sources.
Objects:
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RA (ICRS) DE Designation(s)
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01 33 50.90 +30 39 35.8 M33 = NGC 598
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 51 17 A List of Previous M33 SNR Candidates Excluded
in This Study
table3.dat 63 199 A List of M33 SNR Candidates
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See also:
VII/272 : A catalogue of Galactic supernova remnants (Green, 2014)
J/ApJ/703/370 : Radio SNRs in nearby galaxies (Chomiuk+, 2009)
J/ApJS/187/495 : SNRs in M33 from optical and X-ray (Long+, 2010)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [L10-]
5- 7 A3 --- Name Source identifier ([LBW2010] NNN in Simbad) (G3)
9- 18 F10.7 deg RAdeg Right Ascension in decimal degrees (J2000) (G1)
20- 28 F9.6 deg DEdeg Declination in decimal degrees (J2000) (G1)
30- 34 F5.2 [10-7W] logLHa Log of Hα luminosity; erg/s (G2)
36- 40 F5.2 [10-7W] logLSII Log of [S II] luminosity; erg/s (G2)
42- 44 I3 pc Diam Diameter calculated using 1''=3.88 pc
46- 49 F4.2 --- Ratio Ratio of [S II] to Hα
51 A1 --- Class [HS] Classification (3)
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Note (3): Class as follows:
H = H II regions with [S II]:Hα<0.4, and blue stars inside;
S = Superbubbles (Larger than D=100 pc and a number of blue stars inside).
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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- 3 I3 --- ID [1/199] Index number
5- 14 F10.7 deg RAdeg Right Ascension in decimal degrees (J2000) (G1)
16- 24 F9.6 deg DEdeg Declination in decimal degrees (J2000) (G1)
26- 30 F5.2 [10-7W] logLHa Log of Hα luminosity; erg/s (G2)
32- 36 F5.2 [10-7W] logLSII Log of [S II] luminosity; erg/s (G2)
38- 40 I3 pc Diam Diameter calculated using 1''=3.88 pc (3)
42- 45 F4.2 --- Ratio Ratio of [S II] to Hα
47- 48 A2 --- Morph Morphology type (C,A1,A2,A3,B1,B2,B3)
50- 52 I3 --- N(OB) Number of OB stars (4)
54- 55 A2 --- PType Progenitor type (CC,Ia)
57- 63 A7 --- Com Comments (G3)
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Note (3): For d=800 kpc.
Note (4): Located between the boundary of each SNR candidate and 100 pc
from the center of each SNR candidate.
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Global notes:
Note (G1): Measured in the Hα image.
Note (G2): Calculated using L=4πd2*flux for d=800kpc.
Note (G3): L10 identifier coming from Long et al. (2010, J/ApJS/187/495)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 20-Apr-2017