J/A+A/619/A148 Hot stars observed by XMM-Newton. II. (Naze+, 2018)
Hot stars observed by XMM-Newton. II. A survey of Oe and Be stars.
Naze Y., Motch C.
<Astron. Astrophys. 619, A148 (2018)>
=2018A&A...619A.148N 2018A&A...619A.148N (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; X-ray sources ; Stars, O ; Stars, Be ; Stars, emission
Keywords: stars: early-type - stars: emission-line Be - X-rays: stars -
stars: individual: gamma Cas
Abstract:
We perform a survey of Oe and Be stars in the X-ray range. To this
aim, we cross-correlated XMM-Newton and Chandra catalogs of X-ray
sources with a list of Be stars, finding 84 matches in total. Of
these, 51 objects had enough counts for a spectral analysis. This
paper provides the derived X-ray properties (X-ray luminosities, and
whenever possible, hardness ratios, plasma temperatures, and
variability assessment) of this largest ever sample of Oe and Be
stars. The targets display a wide range in luminosity and hardness. In
particular, the significant presence of very bright and hard sources
is atypical for X-ray surveys of OB stars. Several types of sources
are identified. A subset of stars display the typical characteristics
of O-stars, magnetic OB stars, or pre-main-sequence (PMS) objects:
their Be nature does not seem to play an important role. However,
another subset comprises gamma Cas analogs, which are responsible for
the luminous and hard detections. Our sample contains seven known
gamma Cas analogs, but we also identify eight new gamma Cas analogs
and one gamma Cas candidate. This nearly doubles the sample of such
stars.
Description:
We have performed a survey of Oe and Be stars in the X-ray range using
XMM-Newton, Chandra, and Swift data. To this aim, we have
cross-correlated the BeSS catalog of Be stars with the 3XMM-DR7,
Chandra-CXOGSG, and XMM-SL2 catalogs. We also searched for more recent
public observations of such stars (not yet included in these
catalogs).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 205 84 List of Be stars detected in the X-ray range,
ordered by RA.
table2.dat 113 84 Physical properties of the targets
table3.dat 227 154 *Results of the spectral fitting
table4.dat 77 31 X-ray luminosities in 0.5-10.0keV, corrected for
interstellar absorption, for the simple
detection cases (see Section 4.1.2 for details)
table5.dat 130 18 List of properties of known, new, and candidate
γ Cas analogs, along with two other
peculiar bright sources
refs.dat 217 33 References
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Note on table3.dat: The spectral models are of the form
tbabs x phabs x sum of apec.
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See also:
J/A+A/506/1055 : Hot stars emitting in X-ray. I. (Naze, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq Star index
3- 25 A23 --- SName Simbad star name
26 A1 --- n_SName [:] Note on SName (1)
28- 43 A16 --- SXMM 3XMM source name (JHHMMSS.s+DDMMSS)
45- 47 F3.1 arcsec d3XMM ? Distance between XMM and star positions (2)
49 A1 --- varXMM XMM [y/n] Variability flag
51-100 A50 --- oidXMM ID(s) of the XMM-Newton observation
102-117 A16 --- CXOGSG CXOGSG source name (JHHMMSS.s+DDMMSS)
119-121 F3.1 arcsec dCXO ? Distance between Chandra and star
positions (2)
123 A1 --- varCXO [y/n] Chandra Variability flag
125-144 A20 --- oidCXO ID(s) of the Chandra observation
145 A1 --- n_oidCXO [c] Note on oidCXO (3)
147-162 A16 --- XMMSL2 XMMSL2 source name (JHHMMSS.s+DDMMSS)
164-167 F4.1 arcsec dXMMLS2 ? Distance between XMMSL2 and star
positions (2)
169-205 A37 --- oidSwift ID(s) of the Swift observation
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Note (1): a colon indicates a dubious identification (see section 3 for details)
ALS4570 is used for the BeSS entry HD164492D since the two objects have the
same coordinates.
Note (2): In case of multiple observations (hence multiple detections of a star
under the same X-ray source name), the closest separation is provided.
Note (3): c = 3,4,18,1522,2567/8,3498,3744,4373/4,4395/6,4473/4,
7407/8/9/10/11/12,8568,8589,8895/6/7,13637,14334/5,15546,17735.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq Star index
4- 23 A20 --- SName Simbad star name
26- 43 A18 --- SpType Spectral type (1)
45 A1 --- n_SpType [s] s for Spectral type from Simbad
48- 52 F5.2 mag Vmag V band magnitude
54- 58 F5.3 mag E(B-V) Color excess E(B-V) (2)
60 A1 --- r_E(B-V) ? Reference for E(B-V) (3)
62- 65 I4 pc d Star distance
67- 70 I4 pc e_d standard deviation of d
72- 74 A3 --- r_d Origin of distance (3)
76- 79 F4.2 [Lsun] logLbol Log of bolometric luminosity
81- 84 F4.2 [Lsun] e_logLbol standard deviation of logLbol
86- 90 F5.3 [K] logTeff ? Log of effective temperature after de Jager
& Nieuwenhuijzen (1987A&A...177..217D 1987A&A...177..217D)
92- 94 I3 km/s vsini ? Rotational velocity, mean of values
from all quoted references
96-103 A8 --- r_vsini Origin of vsini measurement, in refs.dat file
105-113 A9 --- Flag Flag (3)
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Note (1): All spectral types are from the BeSS database except for those marked
with s, which are from Simbad. In this context, we note that Simbad mentions
O7V, F5III, and B0.5III as spectral types for the companions of 15 Mon,
CX Dra, and Alfirk, respectively.
Note (2): all E(B-V) extracted from the Stilism interface at
http://stilism.obspm.fr Capitanio et al. (2017A&A...606A..65C 2017A&A...606A..65C) unless
specified otherwise.
Note (3): Flags as follows:
* = indicates a pulsating object
+ = identifies binaries
γ = is set for known γCas analogs
m = indicates magnetic stars
m? = is for claimed magnetic objects.
We note that Alfirk's primary is a pulsating magnetic star, while the
secondary is of Be type; the temperature and rotational velocity values
provided here are those of the secondary.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq Star index
4- 23 A20 --- SName Simbad star name
25- 34 I10 --- OID ? ID of the X-ray observation (1)
36- 41 F6.4 10+22cm-2 NHism Fixed value of the interstellar hydrogen
column density (2)
44- 48 F5.3 10+22cm-2 NH Fitted intrinsic hydrogen column density
50- 54 F5.3 10+22cm-2 e_NH ? Standard deviation of NH (4)
55 A1 --- n_NH [f] f for fixed
57- 62 F6.3 keV kT1 kT of the first thermal component
64- 69 F6.3 keV e_kT1 Standard deviation of kT1 (4)
72- 79 E8.4 cm-5 Norm1 Normalization of the first thermal
component
81- 88 E8.4 cm-5 e_Norm1 Standard deviation of Norm1 (4)
90- 95 F6.3 keV kT2 ? kT of the second thermal component
97-102 F6.3 keV e_kT2 ? Standard deviation of kT2 (4)
105-112 E8.4 cm-5 Norm2 ? Normalization of the second thermal
component
114-121 E8.4 cm-5 e_Norm2 ? Standard deviation of Norm2 (4)
124-127 F4.2 keV kT3 ? kT of the third thermal component
129-132 F4.2 keV e_kT3 ? Standard deviation of kT3 (4)
134-140 E7.3 cm-5 Norm3 ? Normalization of the third thermal
component
142-148 E7.3 cm-5 e_Norm3 ? Standard deviation of Norm3 (4)
151-154 F4.2 --- Chi2 Chi2 of best fit
156-158 I3 --- Dof Degrees of freedom
160-168 E9.4 mW/m2 FXTot Observed X-ray flux (0.5-10KeV)
(in erg/s/cm2)
170-178 E9.4 mW/m2 e_FXTot Standard deviation of FXTot (4)
180-187 E8.4 10-7W LXTotIsm X-ray luminosity (0.5-10keV) using
FX corrected for NHism (in erg/s) (2)
189-196 E8.4 10-7W e_LXTotIsm Standard deviation of LxTotIsm (2)(4)(5)
198-204 F7.4 --- logLX/Lbol Log of Lx/Lbol luminosity ratio
206-211 F6.4 --- e_logLX/Lbol Standard deviation of logLxLbol (4) (5)
213-219 F7.4 --- HR Flux hardness ratio (FXhard/FXsoft) (3)
221-227 F7.4 --- e_HR Standard deviation of HR (4)
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Note (1): Whenever several observations were fitted, the column provides
the corresponding ObsID.
Note (2): The interstellar columns are derived from the color excesses of
Table 2 using the formula of Gudennavar et al. (2012ApJS..199....8G 2012ApJS..199....8G).
Note (3): The hardness ratios are defined by
HR=FXISMcor(hard)/FXISMcor(soft), with soft and hard energy bands
being defined as 0.5-2.0keV and 2.0-10.0keV, respectively
(the total band being 0.5-10.0keV).
Note (4): Errors correspond to 1σ uncertainties.
Note (5): For the X-ray luminosities, the errors combine the distance errors
(see Table 2) with errors on X-ray fluxes (derived from the
"flux err" command in Xspec), but do not integrate the impact of model
choices; errors on log(LX/Lbol_), however, do not depend on distance and
reflect only X-ray flux uncertainties.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Star index
4- 25 A22 --- SName Simbad star name
28- 33 F6.4 10+22cm-2 NHism Value of the interstellar hydrogen
column density (1)
35 A1 --- l_LXTotIsmMin Limit flag on LXTotIsmMin
36- 43 E8.4 10-7W LXTotIsmMin Lower bound of X-ray luminosity
(0.5-10 keV) using FX corrected for
NHism (1)
45- 51 E7.4 10-7W LXTotIsmMax ? Upper bound of X-ray luminosity
(0.5-10 keV) using FX corrected for
NHism (1)
53- 59 E7.4 10-7W e_LXTotIsmMax ? Standard deviation of LXTotIsmMax
(1) (2)
61 A1 --- l_logLX/LbolMin Limit flag on logLxLbolMin
62- 66 F5.2 --- logLX/LbolMin Lower bound of Log of LX/Lbol
luminosity ratio (1)
68- 72 F5.2 --- logLX/LbolMax ? Upper bound of Log of Lx/Lbol
luminosity ratio (1)
74- 77 F4.2 --- e_logLX/LbolMax ? Standard deviation of logLx/LbolMax
(1) (2)
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Note (1): The interstellar columns are derived from the color excesses of
Table 2 using the formula of Gudennavar et al. (2012ApJS..199....8G 2012ApJS..199....8G).
When there were two detections (XMM-Newton and Chandra for 25 Ori XMM-Newton
slew survey and Swift for EM* MWC 659 - for HD215227, only the XMM-Newton
detection was considered, not the new Chandra one), the range reflects the
minimum and maximum fluxes considering available data.
For Cl* NGC 6530 ZCW 221, the XMM-Newton data (Table 3) most probably refer to
a brighter companion (see discussion in Sect. 3), therefore the Chandra data
reported here reflect the stellar X-ray properties better.
Note (2): Errors correspond to 1σ uncertainties, combining the distance
errors (see Table 2) with errors on maximum count rates or photon fluxes.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1 A1 --- Cat [KNCO] Category (1)
3- 4 I2 --- Seq Star index
6- 18 A13 --- SName Simbad star name
20- 36 A17 --- SpType Spectral type (2)
38- 44 F7.4 --- logLX/Lbol Log of LX/Lbol luminosity ratio or lower
value when interval (3)
45- 48 F4.1 --- logLX/Lbol2 ? Upper value of Log of LX/Lbol luminosity
ratio when interval (3)
50- 55 F6.4 --- e_logLX/Lbol ? Standard deviation of LogLX/Lbol
57- 64 E8.3 10-7W LXTotIsm X-ray luminosity (0.5-10 keV) using Fx
corrected for NHism or
lower value when interval (3)
66- 72 E7.3 10-7W LXTotIsm2 ? Upper value of X-ray luminosity
(0.5-10keV) using Fx corrected for NHism
when interval
74- 81 E8.3 10-7W e_LXTotIsm ? Standard deviation of LXTotIsm
83- 90 E8.3 10-7W LXHardIsm ? X-ray luminosity (2-10 keV) using FX
corrected for NHism (3)
92- 99 E8.3 10-7W e_LXHardIsm ? Standard deviation of LXHardIsm
101-106 F6.3 --- HR ? Flux hardness ratio (FX hard/FX soft)
108-113 F6.3 --- e_HR ? Standard deviation of HR (3)
115-116 I2 keV kTmin ? Lower bound kT of the hottest thermal
component (4)
117 A1 --- --- [-]
118-119 I2 keV kTmax ? Upper bound kT of the hottest thermal
component (4)
121 A1 --- Vars [y/n] Short variability flag (5)
122 A1 --- --- [/]
123 A1 --- Varl [y/n] Long variability flag (5)
125-126 I2 0.1nm mEWHa ? Minus equivalent width of Hα
emission line (6)
128-130 I3 km/s vsini ? Projectional rotational velocity (2)
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Note (1): Category as follows:
K = Known γ Cas analogs
N = New γ Cas analogs
C = Candidate γ Cas analog
O = Others
Note (2): Spectral type and projected rotational velocities are reproduced from
Table 2.
Note (3): X-ray properties come from the fits of Table 3 or from Table 4,
except when several observations are available, in which case the
average values and the dispersions around them are provided.
Note (4): When several thermal components were fit, only the temperature of the
hottest one is reported here. For PZGem, only the "high" state (i.e., the
observation with the highest X-ray luminosity) is reported here.
Note (5): The short-term variability flag comes from Table 1, and the long-term
variability flag was set when significant variations of the observed fluxes
(see Table 3) or Swift count rates are detected.
Note (6): Equivalent widths of the Hα line are estimated from the spectra
in the BeSS database taken at the closest time with respect to the X-ray
observation(s) (see also Smith et al., 2016AdSpR..58..782S 2016AdSpR..58..782S for typical
values for the previously known γ Cas analogs).
These BeSS observations are rarely simultaneous. In this context, we note
that Rauw et al. (2013A&A...555L...9R 2013A&A...555L...9R) reported EW(Hα)=-22Å at the
time of the XMM-Newton observation in "high" state, while the emission
reported here is lower because of its later date.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Ref Reference code
5- 23 A19 --- BibCode BicCode
25- 46 A22 --- Aut Author's name
48-217 A170 --- Com Comments
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Acknowledgements:
Christian Motch, christian.motch(at)astro.unistra.fr
References:
Naze, 2009A&A...506.1055N 2009A&A...506.1055N, Paper I Cat. J/A+A/506/1055
(End) Patricia Vannier [CDS] 24-Oct-2018