J/MNRAS/430/1125 RMS survey: NIR spectroscopy of massive YSOs (Cooper+, 2013)
The RMS survey: near-IR spectroscopy of massive young stellar objects.
Cooper H.D.B., Lumsden S.L., Oudmaijer R.D., Hoare M.G., Clarke A.J.,
Urquhart J.S., Mottram J.C., Moore T.J.T., Davies B.
<Mon. Not. R. Astron. Soc., 430, 1125-1157 (2013)>
=2013MNRAS.430.1125C 2013MNRAS.430.1125C
ADC_Keywords: Infrared sources ; Surveys ; Photometry, infrared ; Spectroscopy
Keywords: line: identification - stars: formation - stars: pre-main-sequence -
ISM: jets and outflows
Abstract:
Near-infrared H- and K-band spectra are presented for 247 objects,
selected from the Red MSX Source (RMS) survey as potential young
stellar objects (YSOs). 195 (∼80%) of the targets are YSOs, of which
131 are massive YSOs (LBOL>5x103L☉, M>8M☉). This is
the largest spectroscopic study of massive YSOs to date, providing a
valuable resource for the study of massive star formation. In this
paper, we present our exploratory analysis of the data. The YSOs
observed have a wide range of embeddedness (2.7<AV<114),
demonstrating that this study covers minimally obscured objects right
through to very red, dusty sources. Almost all YSOs show some evidence
for emission lines, though there is a wide variety of observed
properties. The most commonly detected lines are Brγ, H2,
fluorescent FeII, CO bandhead, [FeII] and HeI 2-1 1S-1P, in order of
frequency of occurrence. In total, ∼40% of the YSOs display either
fluorescent FeII 1.6878µm or CO bandhead emission (or both),
indicative of a circumstellar disc; however, no correlation of the
strength of these lines with bolometric luminosity was found. We also
find that ∼60% of the sources exhibit [FeII] or H2 emission,
indicating the presence of an outflow. Three quarters of all sources
have Brγ in emission. A good correlation with bolometric
luminosity was observed for both the Brγ and H2 emission line
strengths, covering 1<LBOL<3.5x105L☉. This suggests that the
emission mechanism for these lines is the same for low-, intermediate-
and high-mass YSOs, i.e. high-mass YSOs appear to resemble scaled-up
versions of low-mass YSOs.
Description:
Spectroscopic observations of the YSO candidates were made using the
UIST instrument at the United Kingdom Infra-Red Telescope (UKIRT)
observatory from 2002 to 2008. 247 objects were successfully observed
over 84 nights. Sources were selected from the ∼2000 candidate MYSOs
found using the MSX catalogue in the preceding stages of the RMS
survey.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 117 247 Table of all spectra
tablea2.dat 108 247 Table showing catalogue and measured magnitudes
for all spectra
tablea3.dat 55 247 Absorption and fobs/fcorr for all objects
tableb1.dat 180 195 YSO and YSO/HIIR emission line fluxes for
Brγ, Br10, Br11, Br12/[FeII] 1.64402um
blend, H2 2.1218um, H2 2.2477um, fluorescent
FeII 1.6878um and HeI 2.0587um.
tableb2.dat 52 195 Equivalent widths of CO(2-0) bandhead emission
for the YSOs with the mean continuum flux
density in the 2.2825-2.2875um region just to
the blue end of the bandhead
tableb3.dat 40 20 List of objects for which either or both of the
Brγ or HeI 2.0587um emission lines have
P-Cygni profiles
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/316 : UKIDSS-DR6 Galactic Plane Survey (Lucas+ 2012)
J/A+A/461/11 : Radio observations of MYSO candidates (Urquhart+, 2007)
J/A+A/474/891 : YSOs in South Gal. plane 13CO observations (Urquhart+, 2007)
J/A+A/476/1019 : Southern candidate massive YSOs RMS survey (Mottram+, 2007)
J/A+A/487/253 : The RMS survey: 13CO observations of YSOs (Urquhart+ 2008)
J/A+A/501/539 : RMS survey. 6cm observations of YSOs (Urquhart+, 2009)
J/A+A/507/795 : The RMS survey: water masers of YSOs (Urquhart+, 2009)
J/A+A/510/A89 : RMS survey of young massive stars in far-IR (Mottram+, 2010)
J/MNRAS/410/1237 : Red MSX survey (RMS) massive young stars (Urquhart+, 2011)
J/A+A/525/A149 : Red MSX Survey: bolometric fluxes of YSOs (Mottram+, 2012)
J/MNRAS/420/1656 : RMS compact HII regions distances (Urquhart+, 2012)
J/MNRAS/437/1791 : RMS survey: molecular observations (Urquhart+, 2014)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Name (GLLL.llll+BB.BBB)
18- 20 A3 --- m_Name Multiplicity index on Name
21 A1 --- n_Name [*] Note on G025.6498+01.0491 (G1)
23- 24 I2 h RAh Right ascension (J2000)
26- 27 I2 min RAm Right ascension (J2000)
29- 33 F5.2 s RAs Right ascension (J2000)
35 A1 --- DE- Declination sign (J2000)
36- 37 I2 deg DEd Declination (J2000)
39- 40 I2 arcmin DEm Declination (J2000)
42- 46 F5.2 arcsec DEs Declination (J2000)
48- 57 A10 "date" Date Observation date
59- 64 F6.2 deg PA [-90/90] Position angle of slit (2)
66- 69 I4 s Texp Exposure time (3)
71- 82 A12 --- Class NIR classification (4)
84- 87 F4.1 kpc Dist ? Distance (5)
88 A1 --- --- [/]
89- 92 F4.1 kpc Dist2 ? Second distance value (5)
94- 99 E6.2 Lsun Lum ? Luminosity (5)
100 A1 --- --- [/]
101-106 E6.2 Lsun Lum2 ? Second luminosity value (5)
108-110 F3.1 GHz RFreq [5/8.6]? Observed radio frequency (5)
112 A1 --- l_FR Limit flag on FR (5)
113-117 F5.1 mJy FR ? Radio flux (5)
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Note (2): The PA was chosen individually for each object from any images that
were available. For the earlier objects, these were 2MASS images, but for the
later runs GLIMPSE images were used. The aim was to centre on the target
object, but to align the slit to catch any extended emission, outflow, or
other interesting nearby objects in the slit at the same time. Some objects
were observed multiple times with different PAs to get spectra of all the
interesting features in the region (see Section 2).
Note (3): The exposure times were chosen based on the magnitudes of the target
object (shown in Table A2).
Note (4): The classification process is described in Section 4, These are
Evolved Star, HIIR, M Star PN, PPN, YSO, YSO/HIIR, or Other
Note (5): The distance, luminosity and radio data were taken from other RMS
publications, listed in Section 1.
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Name (GLLL.llll+BB.BBB)
18- 20 A3 --- m_Name Multiplicity index on Name
21 A1 --- n_Name [*] composite spectrum (G1)
22- 31 A10 --- Cat Catalogue, 2MASS PSC or UKIDSS GPS(1)
33 A1 --- l_JmagC Limit flag on JmagC
34- 39 F6.3 mag JmagC ?=- J magnitude from Cat (1)
41- 45 F5.3 mag e_JmagC ? rms uncertainty on JmagC
47 A1 --- l_HmagC Limit flag on HmagC
48- 53 F6.3 mag HmagC ?=- H magnitude from Cat (1)
55- 59 F5.3 mag e_HmagC ? rms uncertainty on HmagC
61 A1 --- l_KmagC Limit flag on KmagC
62- 67 F6.3 mag KmagC ?=- K magnitude from Cat
69- 73 F5.3 mag e_KmagC ? rms uncertainty on KmagC
75- 79 F5.2 mag Hmag ?=- Measured H magnitude (2)
81- 84 F4.2 mag e_Hmag ?=- Error on Hmag (lower value) (2)
86- 89 F4.2 mag E_Hmag ?=- Error on Hmag (upper value) (2)
91- 96 F6.3 mag Kmag Measured K magnitude
98-102 F5.3 mag e_Kmag Error on Kmag (lower value)
104-108 F5.3 mag E_Kmag Error on Kmag (upper value)
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Note (1): For the catalogue magnitudes, the most appropriate of 2MASS Point
Source Catalogue or UKIDSS Galactic Plane Survey are shown. These are the
magnitudes used for calculating extinction etc. and in Fig. 1 for comparing
measured magnitudes with catalogue magnitudes (see Section 3).
"---" is shown when there are no catalogue magnitudes available at that
wavelength. Where "---" is marked in the error field for the catalogue
magnitudes, the magnitude shown is a lower limit (i.e. an upper limit on the
flux for non-detections or confused fields). Note that this only happens for
2MASS PSC magnitudes; UKIDSS GPS have a different quality flagging system,
as described on the WFCAM Science Archive website.
Note (2): The measured magnitudes were calculated from flux measurements in the
spectra (see Section 3). "---" is marked in the upper error field of the H band
measured magnitude to indicate where the H band flux is so low that the flux
error bar goes below zero, which makes the magnitude error incalculable.
Several of the objects are invisible at H in the spectrum. In these cases,
"---" is marked in the measured H band magnitude fields.
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Name Name (GLLL.llll+BB.BBB)
18- 20 A3 --- m_Name Multiplicity index on Name
22 A1 --- l_AV(JH) Limit flag on AV(JH)
23- 28 F6.3 mag AV(JH) ?=- Absorption calculated using J and H band
magnitudes (1)
30- 34 F5.3 mag e_AV(JH) ? rms uncertainty on AV(JH)
36 A1 --- l_AV(HK) Limit flag on AV(HK)
37- 42 F6.2 mag AV(HK) ?=- Absorption calculated using H and K band
magnitudes (1)
44- 47 F4.2 mag e_AV(HK) ? rms uncertainty on AV(HK)
49- 55 F7.3 --- fc ?=- Correction factor fobs/fcorr (2)
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Note (1): AV was calculated twice for each object using the Draine & Lee
(1984ApJ...285...89D 1984ApJ...285...89D) model, once with J and H band magnitudes ("AV(JH)") and
once with H and K band magnitudes ("AV(HK)" in the table).
Note (2): Correction factor used to correct for the difference between the
observed and catalogue magnitudes; "---" is shown in that column when no
catalogue magnitudes are available for comparison. See Sections 3 and 5.
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Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Name (GLLL.llll+BB.BBB)
18- 20 A3 --- m_Name Multiplicity index on Name
22 A1 --- l_Brg Limit flag on Brγ
23- 32 E10.4 W/m2/um Brg Bracketγ emission line flux (1)
34- 42 E9.4 W/m2/um e_Brg ? rms uncertainty on Brg
44 A1 --- l_Br10 limit flag on Br10
45- 53 E9.4 W/m2/um Br10 ?=- Bracket10 emission line flux (1)
55- 62 E8.4 W/m2/um e_Br10 ? rms uncertainty on Br10
64 A1 --- l_Br11 Limit flag on Br11
65- 73 E9.4 W/m2/um Br11 ?=- Bracket11 emission line flux (1)
75- 82 E8.4 W/m2/um e_Br11 ? rms uncertainty on Br11
84 A1 --- l_Br12+ Limit flag on Br12/[FeII]
85- 93 E9.4 W/m2/um Br12+ ?=- Br12/[FeII] emission flux at 1.64um (1)
95-102 E8.4 W/m2/um e_Br12+ ? rms uncertainty on Br12/[FeII]
104 A1 --- l_H2a Limit flag on H2a
105-112 E8.4 W/m2/um H2a H2 2.1218um emission line flux (1)
114-121 E8.4 W/m2/um e_H2a ? rms uncertainty on H2a
123 A1 --- l_H2b Limit flag on H2b
124-130 E7.4 W/m2/um H2b H2 2.2477um emission line flux (1)
132-138 E7.4 W/m2/um e_H2b ? rms uncertainty on H2b
140 A1 --- l_FeII Limit flag on FeII
141-148 E8.4 W/m2/um FeII ?=- Fluorescent FeII 1.6878um line flux (1)
150-157 E8.4 W/m2/um e_FeII ? rms uncertainty on FeII
160 A1 --- l_HeI Limit flag on HeI
161-169 E9.4 W/m2/um HeI HeI 2.0587um emission line flux (1)
171-178 E8.4 W/m2/um e_HeI ? rms uncertainty on HeI
180 A1 --- Ps [-P] Pfund series presence or absence (2)
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Note (1): A negative value indicates absorption. "---" is marked to indicate
that a measurement was not possible due to a negative H band flux (i.e. where
the object was invisible at H).
Note (2): Hydrogen series to N=5. The presence or absence of the Pfund
series is shown in the "Pfund" column: "P" for present, "-" for absent.
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Byte-by-byte Description of file: tableb2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Name (GLLL.llll+BB.BBB)
18- 20 A3 --- m_Name Multiplicity index on Name
22 A1 --- l_EWCO Limit flag on EWCO (3σ limits) (1)
23- 27 F5.1 0.1nm EWCO CO 2-0 bandhead equivalent width (Å) (2)
29- 31 F3.1 0.1nm e_EWCO ? 1σ error on EWCO
34- 42 E9.4 W/m2/um Fcont Continuum flux density in the 2.2825-2.2875um
region just to the blue end of the bandhead
44- 52 E9.4 W/m2/um e_Fcont 1σ error on Fcont
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Note (1): The negative for G032.4727+00.2041 is used to indicate that while
looking at the spectrum there appears to be absorption, but the detection is
not above the 3σ threshold. All other limits are limits on emission.
Note (2): A positive EW indicates emission.
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Byte-by-byte Description of file: tableb3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Name (GLLL.llll+BB.BBB)
19- 40 A22 --- PCyg P-Cygni profile comments
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Global notes:
Note (G1): *: The final spectrum of G025.6498+01.0491 is a composite of two
spectra, taken on 2007-06-26 and 2007-06-30.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 07-Apr-2014