J/ApJ/725/842 New X-ray-selected SNRs detection with Chandra (Leonidaki+, 2010)
A multiwavelength study of supernova remnants in six nearby galaxies.
I. Detection of new X-ray-selected supernova remnants with Chandra.
Leonidaki I., Zezas A., Boumis P.
<Astrophys. J., 725, 842-867 (2010)>
=2010ApJ...725..842L 2010ApJ...725..842L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Supernova remnants ; X-ray sources ;
Photometry ; Colors ; Spectroscopy
Keywords: galaxies: individual (NGC 2403, NGC 4214, NGC 4395, NGC 4449,
NGC 3077, NGC 5204) - galaxies: star formation -
ISM: supernova remnants - X-rays: galaxies - X-rays: ISM
Abstract:
We present results from a study of the supernova remnant (SNR) population
in a sample of six nearby galaxies (NGC 2403, NGC 3077, NGC 4214,
NGC 4449, NGC 4395, and NGC 5204) based on Chandra archival data. We
have detected 244 discrete X-ray sources down to a limiting flux of
10-15 erg/s/cm2. We identify 37 X-ray-selected thermal SNRs based on
their X-ray colors or spectra, 30 of which are new discoveries. In
many cases, the X-ray classification is confirmed based on counterparts
with SNRs identified in other wavelengths. Three of the galaxies in
our sample (NGC 4214, NGC 4395, and NGC 5204) are studied for the
first time, resulting in the discovery of 13 thermal SNRs. We discuss
the properties (luminosity, temperature, and density) of the
X-ray-detected SNRs in the galaxies of our sample in order to address
their dependence on their environment. We find that X-ray-selected
SNRs in irregular galaxies appear to be more luminous than those in
spirals. We attribute this to the lower metallicities and therefore
more massive progenitor stars of irregular galaxies or the higher
local densities of the interstellar medium. We also discuss the
X-ray-selected SNR populations in the context of the star formation
rate of their host galaxies. A comparison of the numbers of observed
luminous X-ray-selected SNRs with those expected based on the luminosity
functions of X-ray SNRs in the Magellanic Clouds and M33 suggest
different luminosity distributions between the SNRs in spiral and
irregular galaxies with the latter tending to have flatter distributions.
Description:
The sample used for this study consists of six nearby galaxies:
NGC 2403, NGC 5204, NGC 4395, NGC 4449, NGC 3077, and NGC 4214. These
galaxies are selected from the Third Catalog of Bright Galaxies (RC3;
de Vaucouleurs et al. 1995, Cat. VII/155) to be (1) late type (T>4;
Hubble type), (2) close (=<5 Mpc) in order to minimize source
confusion (at 5 Mpc, 1"∼25 pc), (3) at low inclination (=<60°) in
order to minimize internal extinction and projection effects, and (4)
be above the Galactic plane (|b|>20°).
All exposures were obtained with the back-illuminated Advanced CCD
Imaging Spectrometer ACIS-S3 CCD chip (pixel size: 0.49"x0.49"; energy
resolution ∼120 eV at 1 keV; Garmire et al. 2003SPIE.4851...28G 2003SPIE.4851...28G) at
the focal plane of the High Resolution Mirror Assembly
(van Speybroeck et al. 1997SPIE.3113...89V 1997SPIE.3113...89V).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 72 6 *Properties of Our Sample of Galaxies
table5.dat 89 9 Photometric Properties of Potential SNRs in
NGC 3077
table6.dat 89 9 Photometric Properties of Potential SNRs in
NGC 4395
table7.dat 89 18 Photometric Properties of Potential SNRs in
NGC 4449
table8.dat 89 22 Photometric Properties of Potential SNRs in
NGC 4214
table9.dat 89 36 Photometric Properties of Potential SNRs in
NGC 2403
table10.dat 89 3 Photometric Properties of Potential SNRs in
NGC 5204
table11.dat 107 9 X-ray Colors for Potential SNRs in NGC 3077
table12.dat 107 9 X-ray Colors for Potential SNRs in NGC 4395
table13.dat 107 18 X-ray Colors for Potential SNRs in NGC 4449
table14.dat 107 22 X-ray Colors for Potential SNRs in NGC 4214
table15.dat 107 36 X-ray Colors for Potential SNRs in NGC 2403
table16.dat 107 3 X-ray Colors for Potential SNRs in NGC 5204
table17.dat 168 9 Spectral-fitting Results of the Point Sources
in NGC 3077
table18.dat 168 9 Spectral-fitting Results of the Point Sources
in NGC 4395
table19.dat 168 24 Spectral-fitting Results of the Point Sources
in NGC 4449
table20.dat 168 50 Spectral-fitting Results of the Point Sources
in NGC 4214
table21.dat 168 111 Spectral-fitting Results of the SNR Candidates
in NGC 2403
table22.dat 168 18 Spectral-fitting Results of the Point Sources
in NGC 5204
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Note on table1.dat:
Coordinates, diameters, Galactic latitudes, and types of galaxies are from NED
--------------------------------------------------------------------------------
See also:
VII/155 : Third Reference Cat. of Bright Galaxies (RC3)
(de Vaucouleurs+ 1991)
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
J/ApJ/573/306 : Radio emission from supernovae (Eck+, 2002)
J/ApJ/649/730 : ULX population in nearby galaxies from XMM (Winter+, 2006)
J/AJ/137/3869 : Radio SNRs in 4 irregular galaxies (Chomiuk+, 2009)
J/AJ/139/1066 : X-ray view of NGC 2403 central region (Yukita+, 2010)
J/A+A/549/A70 : NGC 4214 multiband images (Hermelo+, 2013)
J/MNRAS/429/189 : SNRs in six nearby galaxies (Leonidaki+, 2013)
J/A+A/569/A68 : Green Bank Telescope observations of NGC 2403
(de Blok+, 2014)
J/AJ/150/94 : Chandra Local Volume Survey. I. (Binder+, 2015)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [NGC]
5- 8 I4 --- NGC Galaxy name (NNNN)
10- 11 I2 h RAh Hour of Right Ascension (J2000)
13- 14 I2 min RAm Minute of Right Ascension (J2000)
16- 19 F4.1 s RAs Second of Right Ascension (J2000)
20 A1 --- DE- Sign of the Declination (J2000)
21- 22 I2 deg DEd Degree of Declination (J2000)
24- 25 I2 arcmin DEm Arcminute of Declination (J2000)
27- 28 I2 arcsec DEs Arcsecond of Declination (J2000)
30- 32 F3.1 Mpc Dist Distance
33 A1 --- n_Dist [efghi] Note on Dist (1)
35- 38 F4.1 arcmin amaj Major axis
40- 43 F4.1 arcmin bmin Minor axis
45- 46 I2 deg Incl [37/62]? Inclination (2)
48- 51 F4.2 10+20cm-2 NH Galactic hydrogen column density (3)
53- 54 I2 deg GLAT [29/82] Galactic latitude
56- 58 I3 deg PA [5/147]? Position angle (4)
60- 67 A8 --- Type Type (5)
69- 72 F4.1 pc Scale Physical scale corresponding to 0.5" at
the distance of each galaxy
--------------------------------------------------------------------------------
Note (1): Note as follows:
e = Freedman & Madore (1988ApJ...332L..63F 1988ApJ...332L..63F);
f = Saha et al. (1994ApJ...425...14S 1994ApJ...425...14S);
g = Annibali et al. (2008AJ....135.1900A 2008AJ....135.1900A);
h = Freedman et al. (1994ApJ...427..628F 1994ApJ...427..628F);
i = Tully (1988ngc..book.....T 1988ngc..book.....T), see Cat. VII/118.
Note (2): Tully (1988ngc..book.....T 1988ngc..book.....T) apart from NGC 4449 (Summers et al.
2003MNRAS.342..690S 2003MNRAS.342..690S).
Note (3): (Leiden/Argentine/Bonn) LAB Survey of Galactic H I.
Note (4): Third Reference Catalog of Bright Galaxies (RC3;
de Vaucouleurs et al. 1995, Cat. VII/155).
Note (5): We note that the SA(s)m galaxies are Magellanic-type which are
classified as irregulars with some spiral structure.
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Byte-by-byte Description of file: table[56789].dat table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Source identifier (LZB_NNN)
9- 10 I2 h RAh Hour of Right Ascension (J2000)
12- 13 I2 min RAm Minute of Right Ascension (J2000)
15- 19 F5.2 s RAs Second of Right Ascension (J2000)
21 A1 --- DE- Sign of the Declination (J2000)
22- 23 I2 deg DEd Degree of Declination (J2000)
25- 26 I2 arcmin DEm Arcminute of Declination (J2000)
28- 32 F5.2 arcsec DEs Arcsecond of Declination (J2000)
34- 38 I5 ct SctsObs Photometric counts in the soft band (G1)
40- 43 I4 ct SctsBkg Background counts in the soft band (G1)
45- 49 I5 ct MctsObs Photometric counts in the medium band (G1)
51- 54 I4 ct MctsBkg Background counts in the medium band (G1)
56- 59 I4 ct HctsObs Photometric counts in the hard band (G1)
61- 64 I4 ct HctsBkg Background counts in the hard band (G1)
66- 70 I5 ct TctsObs Photometric counts in the total band (G1)
72- 76 I5 ct TctsBkg Background counts in the total band (G1)
78- 84 F7.2 --- Area Area ratio (background/source)
86- 89 F4.2 --- EffArea Effective area ratio with respect to a reference
point (see Section 3.3) in the soft-energy band
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1[123456].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Source identifier (LZB_NNN)
9- 13 F5.2 --- Col(S/M) X-ray color in the soft/medium band (G1)
15- 19 F5.3 --- E_Col(S/M) Upper limit uncertainty in Col(S/M) (G1)
21- 25 F5.3 --- e_Col(S/M) Lower limit uncertainty in Col(S/M) (G1)
27- 32 F6.3 --- Col(M/H) X-ray color in the medium/hard band (G1)
34- 37 F4.2 --- E_Col(M/H) Upper limit uncertainty in Col(M/H) (G1)
39- 42 F4.2 --- e_Col(M/H) Lower limit uncertainty in Col(M/H) (G1)
44- 49 F6.3 --- Col(S/H) X-ray color in the soft/hard band (G1)
51- 55 F5.3 --- E_Col(S/H) Upper limit uncertainty in Col(S/H) (G1)
57- 60 F4.2 --- e_Col(S/H) Lower limit uncertainty in Col(S/H) (G1)
62- 64 A3 --- Spectrum [Yes No] Available X-ray spectrum?
(see Section 3.4.2)
66- 80 A15 --- Class Classification of the source according to its
spectrum (see Sections 3.4.2 and 4)
82 A1 --- n_Class [ab] Note on Class (1)
84-103 A20 --- Assoc Multi-wavelength association (2)
105-107 A3 --- n_Assoc Note on Assoc (3)
--------------------------------------------------------------------------------
Note (1): Note as follows:
a = We do not have a spectrum for this source (due to small number of counts)
but its large error bars at the color-color diagram place it on the region
of candidate SNRs;
b = Sources 10, 11, 16, and 23 do not have adequate number of counts to allow
us the extraction of their spectra, but their X-ray colors (within their
error bars) place them in the region of candidate SNRs.
Note (2): X-ray-detected sources by Summers et al. (2003MNRAS.342..690S 2003MNRAS.342..690S), in
table13.
Associations as follows, in table15:
MFBL = Optically identified SNRs by Matonick et al. (1997ApJS..112...49M 1997ApJS..112...49M);
SP = X-ray-identified SNRs by Schlegel & Pannuti (2003AJ....125.3025S 2003AJ....125.3025S);
TH = Radio candidate SNR by Turner & Ho (1994ApJ...421..122T 1994ApJ...421..122T);
Eck = Radio candidate SNR by Eck et al. (2002, J/ApJ/573/306);
? = Large position offsets.
Note (3): Note as follows:
a = Sources identified by Ott et al. (2003ApJ...594..776O 2003ApJ...594..776O);
b = Radio candidate SNR by Rosa-Gonzalez (2005MNRAS.364.1304R 2005MNRAS.364.1304R);
c = The most oxygen-rich SNR known (see Section 2.1);
d = It is also detected in radio as an H II region by Chomiuk & Wilcots
(2009, J/AJ/137/3869);
e = Radio candidate SNR by Vukotic et al. (2005SerAJ.170..101V 2005SerAJ.170..101V), the source
is denoted as ρ;
f = Radio candidate SNRs by Chomiuk & Wilcots (2009, J/AJ/137/3869);
g = The classification criteria of Chomiuk & Wilcots (2009, J/AJ/137/3869) for
radio SNRs is the radio spectral index to be α=←0.2 and Hα
emission associated with the source. In the case of this source, the radio
spectral index is -0.32 but there is no detected Hα emission;
therefore they classify this source as a radio background galaxy;
h = This source is also X-ray-detected (SP-31) by Schlegel & Pannuti
(2003AJ....125.3025S 2003AJ....125.3025S);
i = Also X-ray-detected by Pannuti et al. (2007AJ....133.1361P 2007AJ....133.1361P);
j = This source is also X-ray-detected (SP-16) by Schlegel & Pannuti
(2003AJ....125.3025S 2003AJ....125.3025S) and Pannuti et al. (2007AJ....133.1361P 2007AJ....133.1361P);
k = XRB by Schlegel & Pannuti (2003AJ....125.3025S 2003AJ....125.3025S) while it is also detected
as ULX by Winter et al. (2006, J/ApJ/649/730);
l = Schlegel & Pannuti (2003AJ....125.3025S 2003AJ....125.3025S) have extracted spectra for this
source (SP20) without defining any classification. Also detected as ULX
by Winter et al. (2006, J/ApJ/649/730);
m = Winter et al. (2006, J/ApJ/649/730);
n = Also X-ray-detected (SP-12) by Schlegel & Pannuti (2003AJ....125.3025S 2003AJ....125.3025S)
and Pannuti et al. (2007AJ....133.1361P 2007AJ....133.1361P);
o = Classified as ULX by Winter et al. (2006, J/ApJ/649/730) and
Schlegel & Pannuti (2003AJ....125.3025S 2003AJ....125.3025S).
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Byte-by-byte Description of file: table1[789].dat table2[012].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Stat Statistics used, Χ2 or Cash
8- 14 A7 --- ID Source identifier (LZB_NNN)
16- 19 I4 --- IDobs ? The observation ID used (NNNN)
(only in tables 20-22)
21- 29 A9 --- Model Fitted model (apec, PL, bbody) (1)
31- 36 F6.4 10+22cm-2 NHI ? H I column density
37 A1 --- n_NHI [a] Note on NHI (2)
39- 42 F4.2 10+22cm-2 E_NHI ? Upper limit uncertainty in NHI
44- 47 F4.2 10+22cm-2 e_NHI ? Lower limit uncertainty in NHI
49 A1 --- l_Gamma [>] Limit flag on Gamma
50- 53 F4.2 --- Gamma ? Best-fit value of the power-law photon
index Γ
55- 58 F4.2 --- E_Gamma ? Upper limit unncertainty in Gamma
60- 63 F4.2 --- e_Gamma ? Lower limit uncertainty in Gamma
65 A1 --- l_kT [>] Limit flag on kT
66- 70 F5.2 keV kT ? Thermal component temperature
72 A1 --- lEkT [>] Limit flag on E_kT
73- 77 F5.2 keV E_kT ? Upper limit unncertainty in kT
79- 82 F4.2 keV e_kT ? Lower limit uncertainty in kT
84 A1 --- l_Norm [>] Limit flag on Norm
85- 91 F7.3 --- Norm Normalization factor given in units
of 10-5A (3)
93- 97 F5.2 --- E_Norm ? Upper limit unncertainty in Norm
99-103 F5.3 --- e_Norm ? Lower limit uncertainty in Norm
105-111 F7.2 --- Chi2 ? Χ2 value
113-116 I4 --- DOF [4/1069]? Degrees of freedom
118-123 F6.2 --- Cash ? Cash statistics
125-129 F5.1 % Good ? Goodness-of-fit for Cash statistics
131-136 F6.1 10-18W/m2 Fabs ? Absorbed flux in 0.3-10 keV band
(in 10-15 erg/s/cm2)
138-143 F6.1 10-18W/m2 Funabs ? Unabsorbed flux in 0.3-10 keV band
(in 10-15 erg/s/cm2)
145-148 F4.1 10-7W logL ? Unabsorbed luminosity (0.3-10.0 keV)
using Funabs and the distances from table1
(in erg/s)
150-164 A15 --- Class Source classification based on the X-ray
spectral fits
166-168 A3 --- n_Class Note on Class (4)
--------------------------------------------------------------------------------
Note (1): Fitted model as follows:
apec = Thermal plasma model (Smith et al. 2001ApJ...556L..91S 2001ApJ...556L..91S);
PL = Power-law model;
bbody = Black-body model.
Note (2): Note as follows:
a = Fixed to Galactic line-of-sight value.
Note (3): For apec, A is 10-14(4πD2A)-1int{nenpdV}, where DA is
the angular diameter distance to the source in cm and nenp are the
electron and proton densities, respectively, in cm-3.
For PL, A is: photons/keV/cm2/s at 1 keV.
For bbody, A is: L39/D210, where L39 is the source luminosity
in units of 1039 erg/s and D210 is the distance to the source
in units of 10 kpc.
In tables 20-22: Model normalization for the first observation used. In the
case of multiple observations the number presented is the conversion factor
which is multiplied to the model normalization.
Note (4): Note as follows:
b = Ott et al. (2003ApJ...594..776O 2003ApJ...594..776O) have classified our LZB6, LZB18 as X-ray
SNRs, and LZB2 as an SSS;
c = Radio candidate SNR by Rosa-Gonzalez (2005MNRAS.364.1304R 2005MNRAS.364.1304R);
d = Oxygen-rich SNR detected in all bands;
e = Radio observations by Chomiuk & Wilcots (2009, J/AJ/137/3869) denote this
source as an H II region.
f = Radio candidate SNR by Vukotic et al. (2005SerAJ.170..101V 2005SerAJ.170..101V);
g = Radio candidate SNR by Chomiuk & Wilcots (2009, J/AJ/137/3869);
h = Radio SNR/H II detected by Chomiuk & Wilcots (2009, J/AJ/137/3869).
i = Optically detected SNRs by Matonick et al. (1997ApJS..113..333M 1997ApJS..113..333M);
j = Radio detected SNR by Turner & Ho (1994ApJ...421..122T 1994ApJ...421..122T);
k = Radio detected SNR by Eck et al. (2002, J/ApJ/573/306).
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Global notes:
Note (G1): The four energy bands are:
Soft = 0.3-1.0 keV;
Medium = 1.0-2.5 keV;
Hard = 2.5-7.0 keV;
Total = 0.3-7.0 keV.
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History:
From electronic version of the journal
References:
Leonidaki et al., Paper II., 2013MNRAS.429..189L 2013MNRAS.429..189L, Cat. J/MNRAS/429/189
(End) Prepared by Tiphaine Pouvreau [CDS] 24-Jan-2018