J/ApJS/227/25 6 & 1.3cm deep VLA obs. toward 58 high-mass SFRs (Rosero+, 2016)
Weak and compact radio emission in early high-mass star-forming regions.
I. VLA observations.
Rosero V., Hofner P., Claussen M., Kurtz S., Cesaroni R., Araya E.D.,
Carrasco-Gonzalez C., Rodriguez L.F., Menten K.M., Wyrowski F., Loinard L.,
Ellingsen S.P.
<Astrophys. J. Suppl. Ser., 227, 25-25 (2016)>
=2016ApJS..227...25R 2016ApJS..227...25R (SIMBAD/NED BibCode)
ADC_Keywords: Radio continuum ; Radio sources ; Interstellar medium ;
Interferometry ; H II regions
Keywords: radio continuum: ISM; ISM: jets and outflows; stars: formation;
stars: massive; techniques: interferometric
Abstract:
We present a high-sensitivity radio continuum survey at 6 and 1.3cm
using the Karl G. Jansky Very Large Array toward a sample of 58
high-mass star-forming regions. Our sample was chosen from dust clumps
within infrared dark clouds with and without IR sources (CMC-IRs and
CMCs, respectively), and hot molecular cores (HMCs), with no previous,
or relatively weak radio continuum detection at the 1mJy level. Due to
the improvement in the continuum sensitivity of the Very Large Array,
this survey achieved map rms levels of ∼3-10µJy/beam at
sub-arcsecond angular resolution. We extracted 70 continuum sources
associated with 1.2mm dust clumps. Most sources are weak, compact, and
prime candidates for high-mass protostars. Detection rates of radio
sources associated with the millimeter dust clumps for CMCs, CMC-IRs,
and HMCs are 6%, 53%, and 100%, respectively. This result is
consistent with increasing high-mass star formation activity from CMCs
to HMCs. The radio sources located within HMCs and CMC-IRs occur close
to the dust clump centers, with a median offset from it of 12000au and
4000au, respectively. We calculated 5-25GHz spectral indices using
power-law fits and obtained a median value of 0.5 (i.e., flux
increasing with frequency), suggestive of thermal emission from
ionized jets. In this paper we describe the sample, observations, and
detections.
Description:
VLA continuum observations (project codes 10B-124 and 13B-210) at 6
and 1.3cm were made for all sources in the sample.
The 6cm observations were made in the A configuration between 2011
June and August, providing a typical angular resolution of about
0.4".
The 1.3cm observations were made in the B configuration, acquiring the
first half of the data between 2010 November and 2011 May, and the
second half between 2013 November and 2014 January.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 119 116 Observed 58 clumps
table4.dat 96 660 *Continuum parameters
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Note on table4.dat: Table 4 reports the parameters for all detected radio
sources within the 1.8' FWHM primary beam at 25.5GHz.
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See also:
J/A+A/550/A21 : Massive star-forming regions radio lines (Sanchez-Monge+, 2013)
J/A+A/552/A40 : MSX high-contrast IRDCs with NH3 (Chira+, 2013)
J/ApJ/756/60 : A 3mm line survey in 37 IR dark clouds (Sanhueza+, 2012)
J/ApJ/715/310 : Early stages of star formation in IRDCs (Rathborne+, 2010)
J/ApJ/681/428 : BLAST sources in Galactic plane survey (Chapin+, 2008)
J/ApJ/641/389 : Millimetric observations of IRDC cores (Rathborne+, 2006)
J/A+A/398/901 : VLA survey at 6 cm in the Lockman Hole (Ciliegi+, 2003)
J/ApJ/566/945 : Massive star forming regions at 1.2mm (Beuther+, 2002)
J/A+A/336/339 : VLA observations of ultracompact HII regions (Molinari+ 1998)
J/ApJS/91/659 : Ultracompact HII regions radio images (Kurtz+ 1994)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Region Region identifier
18 A1 --- Band [CK] VLA band (C=4.5-5.0GHz (6cm) or
K=22-24GHz (1.3cm))
20- 21 I2 h RAh Hour of Right Ascension (J2000)
23- 24 I2 min RAm Minute of Right Ascension (J2000)
26- 29 F4.1 s RAs Second of Right Ascension (J2000)
31 A1 --- DE- Sign of the Declination (J2000)
32- 33 I2 deg DEd Degree of Declination (J2000)
35- 36 I2 arcmin DEm Arcminute of Declination (J2000)
38- 39 I2 arcsec DEs Arcsecond of Declination (J2000)
41 A1 --- Mult [c] Multiplicity flag (1)
43- 49 F7.3 deg GLON Galactic longitude
51- 56 F6.3 deg GLAT Galactic latitude
58- 61 F4.2 arcsec Bmaj [0.3/0.7] Beam major axis
63- 66 F4.2 arcsec Bmin [0.2/0.4] Beam minor axis
68- 74 F7.2 deg Bsize [-179/87] Beam size
76- 79 F4.1 uJy/beam rms [4/30] Root mean square
81- 82 A2 --- Det Detection code (2)
84- 89 A6 --- Type Region type (3)
91- 98 A8 kpc Dist Distance
100-110 A11 kLsun Lum Bolometric luminosity
112-113 A2 --- f_Lum Flag on Lum (4)
115-119 A5 --- Ref Reference(s) for the distance and
luminosity (5)
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Note (1):
c = Several sources within 25.5GHz primary beam; same pointing center at
a nearby clump.
Note (2): (D)etected and (ND) not detected within mm clump.
Note (3): Region type as follows:
HMC = hot molecular core (50 instances; 25 unique sources). These are
high-luminosity (>103L☉) IRAS sources associated with
dense gas, outflows, and masers.
CMC = cold molecular clump (36 instances; 18 unique sources). The sources
from this target group were mainly selected from the original sample
of Rathborne+ (2006, J/ApJ/641/389).
CMC-IR = cold molecular clumps with mid-IR association (30 instances;
15 unique sources). CMC-IRs representing an earlier evolutionary phase
of high-mass star formation, they are cold (T<25K),
massive (M>100M☉) clumps found by MSX and Spitzer IRDC surveys.
See section 2.1 for further details.
Note (4): Flag as follows:
a = Luminosity is corrected for the adopted distance.
b = Lower and upper limits of luminosity from Rathborne+ (2006, J/ApJ/641/389).
Note (5): Reference as follows:
1 = Forbrich et al. (2004ApJ...602..843F 2004ApJ...602..843F);
2 = Linz et al. (2010A&A...518L.123L 2010A&A...518L.123L);
3 = Pillai et al. (2006A&A...447..929P 2006A&A...447..929P);
4 = Henning et al. (2010A&A...518L..95H 2010A&A...518L..95H);
5 = Xu et al. (2011ApJ...733...25X 2011ApJ...733...25X);
6 = Sridharan et al. (2002ApJ...566..931S 2002ApJ...566..931S);
7 = Sakai et al. (2012ApJ...747..140S 2012ApJ...747..140S);
8 = Rathborne et al. (2010, J/ApJ/715/310);
9 = Sato et al. (2014ApJ...793...72S 2014ApJ...793...72S);
10 = Moscadelli et al. (2013A&A...558A.145M 2013A&A...558A.145M);
11 = Beuther et al. (2010A&A...518L..78B 2010A&A...518L..78B);
12 = Sanhueza et al. (2012, J/ApJ/756/60;
13 = Lu et al. (2014ApJ...790...84L 2014ApJ...790...84L);
14 = Chira et al. (2013, J/A+A/552/A40;
15 = Brunthaler et al. (2009ApJ...693..424B 2009ApJ...693..424B);
16 = Araya et al. (2008ApJS..178..330A 2008ApJS..178..330A);
17 = Fazal et al. (2008ApJ...688L..41F 2008ApJ...688L..41F);
18 = Kurayama et al. (2011PASJ...63..513K 2011PASJ...63..513K);
19 = Lopez-Sepulcre et al. (2011A&A...526L...2L 2011A&A...526L...2L);
20 = Wu et al. (2014A&A...566A..17W 2014A&A...566A..17W);
21 = Nguyen Luong et al. (2011A&A...535A..76N 2011A&A...535A..76N);
22 = Zhang et al. (2007A&A...470..269Z 2007A&A...470..269Z);
23 = Chapin et al. (2008, J/ApJ/681/428);
24 = Moscadelli et al. (2011A&A...526A..66M 2011A&A...526A..66M).
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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- 16 A16 --- Region Region identifier
18- 31 A14 --- Radio Radio source identifier (1)
33- 36 F4.1 GHz Freq Radio source frequency (4.9, 7.4, 20.9 or 25.5)
38 A1 --- f_Freq [d] d=Map at this frequency is not available
40- 41 I2 h RAh ? Hour of Right Ascension (J2000)
43- 44 I2 min RAm ? Minute of Right Ascension (J2000)
46- 50 F5.2 s RAs ? Second of Right Ascension (J2000)
52 A1 --- DE- Sign of the Declination (J2000)
53- 54 I2 deg DEd ? Degree of Declination (J2000)
56- 57 I2 arcmin DEm ? Arcminute of Declination (J2000)
59- 62 F4.1 arcsec DEs ? Arcsecond of Declination (J2000)
64- 67 I4 uJy Snu [23/9450]? Flux density at Freq
69 A1 --- f_Snu [ce] Flag on Snu (2)
71 A1 --- l_Inu Limit flag on Inu
72- 75 I4 uJy/beam Inu [15/3940]? Peak intensity at Freq
77 A1 --- f_Inu [bc] Flag on Inu (2)
80 A1 --- Morph Morphology (C=compact or R=resolved)
82 A1 --- Assoc [n/y] A millimeter association?
84 A1 --- f_Assoc [a] Flag on Assoc (2)
86 A1 --- l_SpIndex Limit flag on SpIndex
89- 92 F4.1 --- SpIndex [-1.6/1.8]? Spectral index of radio observations
94- 96 F3.1 --- e_SpIndex [0.1/1.6]? Uncertainty in SpIndex (3)
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Note (1): In Table 1 column "Det" we indicate whether there are radio sources
coincident with these millimeter clumps. To distinguish these sources
further, in this table, for each region we label radio detections that
are located within the millimeter clump with capital letters,
i.e., "A," "B," "C," etc., from east to west. Sources that are within
the 25.5GHz FWHM primary beam but outside of the millimeter clump are
labeled by their Galactic coordinates. Contour images for all radio
sources associated with millimeter clumps are shown in Figure 2.
Note (2): Flag as follows:
a = 1.2 mm continuum data is not available for this source. The
association was based on a typical size for each type of clump.
b = Non-detection. Upper limit is 3σ value in map.
c = Components have a bridge blending emission.
e = Contains embedded component B.
Note (3): The uncertainty is 1σ statistical error from the fit. Several
sources in our survey are very weak; the occasional presence of
image artifacts (e.g., the emission lying in a negative bowl)
inhibited in some cases an accurate measurement of the flux
density. In these cases the spectral index was determined using
the peak intensity instead of the total flux density.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 11-Jan-2017