J/ApJS/208/28 Hα survey in the ONC (Szegedi-Elek+, 2013)
A new Hα emission-line survey in the Orion Nebula Cluster.
Szegedi-Elek E., Kun M., Reipurth B., Pal A., Balazs L.G., Willman M.
<Astrophys. J. Suppl. Ser., 208, 28 (2013)>
=2013ApJS..208...28S 2013ApJS..208...28S
ADC_Keywords: Equivalent widths ; Photometry, RI ; Spectra, red ; YSOs ;
Cross identifications ; Surveys
Keywords: ISM: individual: Orion Nebula Cluster -
stars: emission-line, Be - stars: pre-main sequence
Abstract:
We present results from an Hα emission line survey in a 1 deg2
area centered on the Orion Nebula Cluster, obtained with the Wide
Field Grism Spectrograph 2 on the 2.2 m telescope of the University of
Hawaii. We identified 587 stars with Hα emission, 99 of which,
located mainly in the outer regions of the observed area, have not
appeared in previous Hα surveys. We determined the equivalent
width (EW) of the line and, based on this, classified 372 stars as
classical T Tauri stars (CTTSs) and 187 as weak-line T Tauri stars
(WTTSs). Simultaneous r', i' photometry indicates a limiting magnitude
of r' ∼ 20 mag, but the sample is incomplete at r' > 17 mag. The
surface distribution of the Hα emission stars reveals a
clustered population and a dispersed population, the former consisting
of younger and more massive young stars than the latter. Comparison of
the derived EWs with those found in the literature indicates
variability of the Hα line. We found that the typical amplitudes
of the variability are not greater than a factor of two to three in
most cases. We identified a subgroup of low-EW stars with infrared
signatures indicative of optically thick accretion disks. We studied
the correlations between the EW and other properties of the stars.
Based on literature data, we examined several properties of our CTTS
and WTTS subsamples and found significant differences in mid-infrared
color indices, average rotational periods, and spectral energy
distribution characteristics of the subsamples.
Description:
We observed the ONC, centered on the Trapezium, with the Wide Field
Grism Spectrograph-2 (WFGS2) installed on the University of Hawaii
2.2m telescope, on the five nights of 2010 December 31, 2011 January
2, 2011 January 25, 2011 February 27, and 2011 October 16. We covered
an area of almost 1deg2 centered on RAJ2000=5:35:16.4 and
DEJ2000=-5:23:25 with a mosaic of 25 overlapping fields. We used a
300line/mm grism blazed at 6500Å and providing a dispersion of
3.8Å/pixel and a resolving power of 820. The Hα filter had a
500Å passband centered near 6515Å.
Direct images of each field of the mosaic with the same instrument
were obtained through r' and i' filters immediately before the
spectroscopic exposures. One exposure was taken at each position and
in each filter with integration time of 60s.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 220 372 Hα emission stars classified as classical
T Tauri stars
table2.dat 124 187 Hα emission stars classified as weak-line
T Tauri stars
table3.dat 64 28 Hα stars without classification
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See also:
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
III/177 : H-alpha emission stars in the Orion region (Wiramihardja+ 1993)
V/73 : Emission-Line Stars of the Orion Population (Herbig+ 1988)
II/309 : Halpha emission stars in the Orion Nebula (Parsamian+, 1982)
II/171 : Parenago Catalog of Stars in Orion Nebula (Parenago 1954)
J/ApJ/733/50 : MIR phot. monitoring of the ONC (Morales-Calderon+, 2011)
J/A+A/533/A38 : Extinction map of OMC-1 (Scandariato+, 2011)
J/ApJS/183/261 : Optical photometry of the ONC (Da Rio+, 2009)
J/ApJ/677/401 : Xray properties of protostars in ONC (Prisinzano+, 2008)
J/ApJ/676/1109 : Velocities of stars in the ONC (Furesz+, 2008)
J/AJ/136/2136 : HST/ACS Atlas of Great Orion Nebula proplyds (Ricci+, 2008)
J/ApJ/671/605 : NGC 2264 and ONC PMS stars in the infrared (Cieza+, 2007)
J/ApJS/160/450 : X-ray emission in ONC young stars (Flaccomio+, 2005)
J/ApJS/160/319 : COUP: observations and source lists (Getman+, 2005)
J/A+A/396/513 : Stellar Rotation in the Orion Nebula Cluster (Herbst+, 2002)
J/ApJ/574/258 : X-ray-emitting young stars in the ONC (Feigelson+, 2002)
J/AJ/121/3160 : JHK photometry near the Trapezium region (Carpenter+, 2001)
J/AJ/121/1676 : ONC low-mass stars photometry (Rebull+, 2001)
J/AJ/119/3026 : Circumstellar disk candidates in Orion (Rebull+, 2000)
J/AJ/116/1816 : JHKLMNOPQ photometry in Orion cluster (Hillenbrand+, 1998)
J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- 2MASS 2MASS identifier (except "d" flagged)
21 A1 --- n_2MASS [*d] New/UKIDSS source (G1)
23 A1 --- l_EWa Limit flag on EWa
24- 29 F6.1 0.1nm EWa ? Equivalent width measured in 2010/12/31 (G2)
31- 34 F4.1 0.1nm e_EWa ? Uncertainty in EWa
36- 40 F5.1 0.1nm EWa2 ? 2nd equivalent width measured in 2010/12/31 (G2)
42- 44 F3.1 0.1nm e_EWa2 ? Uncertainty in EWa2
46- 50 F5.1 0.1nm EWb ? Equivalent width measured in 2011/01/02 (G2)
52- 56 F5.1 0.1nm e_EWb ? Uncertainty in EWb
58- 62 F5.1 0.1nm EWb2 ? 2nd equivalent width measured in 2011/01/02 (G2)
64- 67 F4.1 0.1nm e_EWb2 ? Uncertainty in EWb2
69 A1 --- l_EWc Limit flag on EWc
71- 75 F5.1 0.1nm EWc ? Equivalent width measured in 2011/01/25 (G2)
77- 81 F5.1 0.1nm e_EWc ? Uncertainty in EWc
83- 87 F5.1 0.1nm EWc2 ? 2nd equivalent width measured in 2011/01/25
89- 92 F4.1 0.1nm e_EWc2 ? Uncertainty in EWc2
94- 98 F5.1 0.1nm EWd ? Equivalent width measured in 2011/02/27 (G2)
100-105 F6.2 0.1nm e_EWd ? Uncertainty in EWd
107-110 F4.1 0.1nm EWd2 ? 2nd equivalent width measured in 2011/02/27
112-114 F3.1 0.1nm e_EWd2 ? Uncertainty in EWd2
116-120 F5.1 0.1nm EWe ? Equivalent width measured in 2011/10/16 (G2)
122-125 F4.1 0.1nm e_EWe ? Uncertainty in EWe
127-131 F5.2 mag r'mag ? The r' band magnitude converted to SDSS system
133-137 F5.2 mag r'-i' ? The (r'-i') color index
139-220 A82 --- CID Cross identification(s)
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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- 19 A19 --- 2MASS 2MASS identifier (except "d" flagged)
21 A1 --- f_2MASS [*d+] New, UKIDSS or blended source (G1)
23 A1 --- l_EWa Limit flag on EWa
24- 28 F5.1 0.1nm EWa ? Equivalent width measured in 2010/12/31 (G2)
30- 32 F3.1 0.1nm e_EWa ? Uncertainty in EWa
34 A1 --- l_EWb Limit flag on EWb
35- 39 F5.1 0.1nm EWb ? Equivalent width measured in 2011/01/02 (G2)
41- 43 F3.1 0.1nm e_EWb ? Uncertainty in EWb
45 A1 --- l_EWc Limit flag on EWc
46- 50 F5.1 0.1nm EWc ? Equivalent width measured in 2011/01/25 (G2)
52- 55 F4.1 0.1nm e_EWc ? Uncertainty in EWc
57- 59 F3.1 0.1nm EWd ? Equivalent width measured in 2011/02/27 (G2)
61- 63 F3.1 0.1nm e_EWd ? Uncertainty in EWd
65- 68 F4.1 0.1nm EWe ? Equivalent width measured in 2011/10/16 (G2)
70- 72 F3.1 0.1nm e_EWe ? Uncertainty in EWe
74- 77 F4.1 mag r'mag ? The r' band magnitude converted to SDSS system
79- 83 F5.2 mag r'-i' ? The (r'-i') color index
85-124 A40 --- CID Cross identification(s)
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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- 17 A17 --- 2MASS 2MASS name (JHHMMSSss+DDMMSSs)
18 A1 --- f_2MASS [*] New source (G1)
20- 64 A45 --- CID Cross identification(s)(s)
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Global notes:
Note (G1):
* = Indicates source not detected by previous Hα surveys.
+ = 2MASS identifier indicates 1 source, but this observation contains 2
sources, just one of these shows Hα emission.
d = Indicates UKIDSS source (UGCS; JHHMMSS.ss+DDMMSS.s format).
Note (G2): In units of Angstroms.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 04-Nov-2013