J/ApJ/562/446 X-rays and protostars in Trifid nebula (Rho+, 2001)
X-rays and protostars in the Trifid nebula.
Rho J., Corcoran M.F., Chu Y.-H., Reach W.T.
<Astrophys. J. 562, 446 (2001)>
=2001ApJ...562..446R 2001ApJ...562..446R
ADC_Keywords: H II regions ; X-ray sources ; YSOs ; Stars, pre-main sequence
Keywords: H II regions - infrared: stars - stars: formation -
X-rays: individual (Trifid Nebula)
Abstract:
The Trifid Nebula is a young HII region, recently rediscovered as a
"pre-Orion" star-forming region, containing protostars undergoing
violent mass ejections visible in optical jets as seen in images from
the Infrared Space Observatory and the Hubble Space Telescope. We
report the first X-ray observations of the Trifid Nebula using ROSAT
and ASCA. The ROSAT image shows a dozen X-ray sources, with the
brightest X-ray source being the O7 star, HD 164492, which provides
most of the ionization in the nebula. We also identify 85 T Tauri star
and young, massive star candidates from near-infrared colors using the
JHKs color-color diagram from the Two-Micron All-Sky Survey (2MASS).
Ten X-ray sources have counterpart near-infrared sources. The 2MASS
stars and X-ray sources suggest there are potentially numerous
protostars in the young HII region of the Trifid. ASCA
moderate-resolution spectroscopy of the brightest source shows hard
emission up to 10keV with a clearly detected FeK line.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table13.dat 132 13 List of the 12 sources detected in the PSPC Image
of the Trifid nebula and infrared counterparts
table2.dat 29 85 2MASS young stellar object and T Tauri star
candidates in the Trifid nebula
--------------------------------------------------------------------------------
See also:
B/2mass : The 2MASS database (IPAC/UMass, 2000)
Byte-by-byte Description of file: table13.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [RXT]
5- 6 I2 --- RXT RXT designation
8- 9 I2 h RAh Right ascension (J2000.0)
11- 12 I2 min RAm Right ascension (J2000.0)
14- 18 F5.2 s RAs Right ascension (J2000.0)
20 A1 --- DE- Declination sign (J2000.0)
21- 22 I2 deg DEd Declination (J2000.0)
24- 25 I2 arcmin DEm Declination (J2000.0)
27- 30 F4.1 arcsec DEs Declination (J2000.0)
32- 37 F6.4 ct/s CR Count Rate
39- 44 F6.4 ct/s e_CR rms uncertainty on CR
46- 48 F3.1 ---- Det Detection (1σ)
50- 54 F5.2 [10-10W/m2] logLX ? X-ray luminosity
56 A1 --- Note [ab] Individual notes (1)
58- 61 A4 --- Type Type of the 2MASS counterparts (2)
63- 66 F4.1 arcsec dproj ? Projected distance between the X-ray and
2MASS sources
68- 69 I2 h RA2h ? 2MASS counterpart right ascension (J2000)
71- 72 I2 min RA2m ? 2MASS counterpart right ascension (J2000)
74- 77 F4.1 s RA2s ? 2MASS counterpart right ascension (J2000)
79 A1 --- DE2- 2MASS counterpart declination sign (J2000)
80- 81 I2 deg DE2d ? 2MASS counterpart declination (J2000)
83- 84 I2 arcmin DE2m ? 2MASS counterpart declination (J2000)
86- 89 F4.1 arcsec DE2s ? 2MASS counterpart Declination (J2000)
91- 95 F5.2 mag Jmag ? 2MASS counterpart J magnitude
97-101 F5.2 mag Hmag ? 2MASS counterpart H magnitude
103-107 F5.2 mag Ksmag ? 2MASS counterpart Ks magnitude
109-132 A24 --- Com Comments (3)
--------------------------------------------------------------------------------
Note (1): Individual notes as follows:
a = RXT 8 is HD 164492 (O7 star) and/or YSO (TC1 in Cernicharo et al.,
1998Sci...282..462C 1998Sci...282..462C), and see table4 for Spectral Fit Results
b = RXT 11 also coincides with HD 313596 (B8 star)
Note (2): Notes for the 2MASS sources as follows:
TTS = T Tauri star
YSO = massive young stellar object
red = red 2MASS star
Mult = Multiple
Note (3): In the comments:
J="fill": the J-band photometry is measured in band-filled within
the aperture, indicating their photometric uncertainties are large.
High psf Δχ2: the goodness of the fit of a point-spread
function is high, indicating the sources are either extended or
unresolved double sources.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- [RCC2001] Object name (YSO NN or TTS NN)
8- 29 A22 --- 2MASS 2MASS designation (1)
--------------------------------------------------------------------------------
Note (1): 2MASSI and 2MASSW indicate the Incremental Release and Working
Database catalogs, respectively.
--------------------------------------------------------------------------------
Table 4: Spectral Fit Results from Simultaneous Fit Using ASCA/PSPC
--------------------------------------------------------------------------------
Parameters Trifid
--------------------------------------------------------------------------------
ISM NH (1021cm-2) ∼3
T2 3.3±0.6keV (=3.9x107K)
log EM2(cm-3) 55.8
Wind NH, hot component (1021cm-2) 2.7+2.3-2.0
T1 0.14+0.06-0.04keV (=1.2x106K)
log EM1(cm-3) 57.4
Wind NH, 1 component (1021cm-2) 5.9+1.1-0.9
Flux 2±0.5x10-12
Unabsorbed flux 8±2x10-11
Luminosity (ergs/s) 2.5x1034 [d(kpc)/(1.67kpc)]2
Fe K Line central energy (keV) 6.65+0.1-0.2
Fe K equivalent width (keV) 1.7±0.3
Fe K flux (photons/s/cm2) 6(±0.4)x10-4
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 29-Apr-2002