J/MNRAS/483/1437 Star formation in the Carina Nebula (Contreras+, 2019)
Environmental conditions shaping star formation: the Carina Nebula.
Contreras Y., Rebolledo D., Breen S.L., Green A.J., Burton M.G.
<Mon. Not. R. Astron. Soc., 483, 1437-1451 (2019)>
=2019MNRAS.483.1437C 2019MNRAS.483.1437C (SIMBAD/NED BibCode)
ADC_Keywords: Masers ; Interstellar medium ; Radio lines ; Velocity dispersion
Keywords: masers - stars: formation - ISM: molecules - radio lines: ISM
Abstract:
Using the Mopra telescope, we have targeted 61 regions in the Carina
Nebula, covering an area of 1.5deg2, of bright and compact 870µm
dust continuum emission for molecular line emission from a host of 16
spectral lines at 3mm, including several dense gas tracers. We found
that the clumps detected in Carina in general have in average higher
temperatures (27K compared to 21K), and lower masses (214M☉
compared to 508M☉) than clumps located at a similar distance to
us in the Galactic plane. We compare the properties of the molecular
line emission of these clumps with the MALT90 survey, finding that the
detection rates of the molecular lines are similar to MALT90 clumps
that are classified as photodissociation regions. However, most of the
clumps located within 10arcmin of η Carina have little molecular
line emission detected in our observations. Given the lack of maser
detection in the Carina region, we also compared the properties of the
clumps in Carina to those of Galactic clumps associated with 6.7-GHz
methanol masers. We found that the clumps in Carina are warmer, less
massive, and show less emission from the four most commonly detected
molecules, HCO+, N2H+, HCN, and HNC, compared to clumps
associated with masers in the Galactic Plane. Overall our results are
consistent with the scenario in which the high radiation field of
η Carina is dramatically affecting its local environment, and
therefore the chemical composition of the dense clumps.
Description:
We targeted 61 dense clumps that were selected based on their dust
continuum emission at 870µm from the ATLASGAL survey (Schuller et
al. 2009A&A...504..415S 2009A&A...504..415S; Contreras et al. 2013A&A...549A..45C 2013A&A...549A..45C, Cat.
J/A+A/549/A45; Urquhart et al. 2014A&A...568A..41U 2014A&A...568A..41U, Cat.
J/A+A/568/A41). The ATLASGAL survey has produced a complete census of
dense high-mass clumps over a range of evolutionary stages, ranging
from quiescent pre-stellar clumps, showing no emission at infrared
wavelengths to those that contain proto-stars and more evolved clumps
associated with HII regions and PDRs. In Carina, ATLASGAL detected
91870 µm compact clumps, of which we targeted the brightest 61 with
Mopra, in order to analyse the properties of the accompanying
molecular line emission. The 870µm flux of the 61 target clumps
range from 0.47 to 4.53Jy/Beam. Their angular sizes range from 9 to
166arcsec, which at the distance of the Carina Nebula (2.3kpc; Smith
et al. 2010MNRAS.405.1153S 2010MNRAS.405.1153S) corresponds to physical sizes of
0.1-1.9pc, with a mean value of 0.6pc.
Each of the target 61 ATLASGAL clumps was observed using the Mopra
telescope and the wide-band Mopra Spectrometer (MOPS) during 17
separate observing days between 2014 October 16 and 2015 July 20, and
between 2018 April 30 and May 2. We used the same frequency
configuration as that used by the MALT90 survey (Jackson et al.
2013PASA...30...57J 2013PASA...30...57J), allowing 16 spectral lines near 90GHz to be
observed simultaneously. The combination of these molecular
transitions span a large range of excitation energies (from 5 to 200K)
and critical densities (from 105 to 106cm-3), tracing distinct
physical conditions within the clumps such as high-density gas, hot
core chemistry, PDRs, shocks, outflows, and ionized gas.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 122 71 Properties of the dust continuum and molecular
line emission
table3.dat 98 71 Properties of the molecular line emission
table4.dat 59 62 Physical properties the clumps derived from
their dust continuum emission
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- Name Clump name (AGALLLL.lll+BB.bbb)
19- 21 A3 --- m_Name Component designation, (N), (1)
23- 27 F5.2 Jy/beam F870 ? Peak flux at 870µm from the Large APEX
Bolometer Camera (LABOCA)
29- 32 F4.2 K TAHCO ? Peak antenna temperature obtained from
the Gaussian fits of the HCO+ emission
34- 37 F4.2 K e_TAHCO ? Error on TAHCO
39- 43 F5.2 km/s vLSRHCO ? Velocity of the peak obtained from the
Gaussian fits of the HCO+ emission
45- 48 F4.2 km/s e_vLSRHCO ? Error on vLSRHCO
50- 53 F4.2 km/s vdispHCO ? Velocity dispersion obtained from the
Gaussian fits of the HCO+ emission
55- 58 F4.2 km/s e_vdispHCO ? Error on vdispHCO
60- 63 F4.2 K TAHCN ? Peak antenna temperature obtained from
the Gaussian fits of the HCN emission
65- 68 F4.2 K e_TAHCN ? Error on TAHCN
70- 74 F5.2 km/s vLSRHCN ? Velocity of the peak obtained from the
Gaussian fits of the HCN emission
76- 79 F4.2 km/s e_vLSRHCN ? Error on vLSRHCN
81- 84 F4.2 km/s vdispHCN ? Velocity dispersion obtained from the
Gaussian fits of the HCN emission
86- 89 F4.2 km/s e_vdispHCN ? Error on vdispHCN
91- 94 F4.2 K TAHNC ? Peak antenna temperature obtained from the
Gaussian fits of the HNC emission
96-100 F5.2 K e_TAHNC ? Error on TAHNC
102-106 F5.2 km/s vLSRHNC ? Velocity of the peak obtained from the
Gaussian fits of the HNC emission
108-111 F4.2 km/s e_vLSRHNC ? Error on vLSRHNC
113-116 F4.2 km/s vdispHNC ? Velocity dispersion obtained from the
Gaussian fits of the HNC emission
118-122 F5.3 km/s e_vdispHNC ? Error on vdispHNC
--------------------------------------------------------------------------------
Note (1): Some sources have several components along the line of sight. For
these, each component has been fitted separately and the values for
each fit is given in this table.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- Name Clump name (AGALLLL.lll+BB.bbb)
19- 21 A3 --- m_Name Component designation, (N), (1)
23- 28 F6.2 K TexN2H ? Excitation temperature derived from the
hyperfine fit to the N2H+ emission
30- 33 F4.2 K e_TexN2H ? Error on TexN2H
35- 38 F4.2 --- tau ? Opacity derived from the hyperfine fit to
the N2H+ emission
40- 43 F4.2 --- e_tau ? Error on tau
45- 50 F6.2 km/s vLSRN2H ? Velocity of the peak derived from the
hyperfine fit emission
52- 55 F4.2 km/s e_vLSRN2H ? Error on vLSRN2H
57- 60 F4.2 km/s vdispN2H ? Velocity dispersion derived from the
hyperfine fit emission
62- 66 F5.3 km/s e_vdispN2H ? Error on sigmaN2H
68- 71 F4.2 K TAC2H ? Peak intensity obtained from the Gaussian
fits of the C2H emission
73- 76 F4.2 K e_TAC2H ? Error on TAC2H
78- 83 F6.2 km/s vLSRC2H ? Velocity of the peak obtained from the
Gaussian fits of the C2H emission
85- 88 F4.2 km/s e_vLSRC2H ? Error on vLSRC2H
90- 93 F4.2 km/s vdispC2H ? Velocity dispersion obtained from the
Gaussian fits of the C2H emission
95- 98 F4.2 km/s e_vdispC2H ? Error on sigmaC2H
--------------------------------------------------------------------------------
Note (1): Some sources have several components along the line of sight. For
these, each component has been fitted separately and the values for
each fit is given in this table.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- Name Clump name (AGALLLL.lll+BB.bbb)
20- 23 I4 Msun Mass ? Clump mass obtained from the density and
temperature mass computed by Rebolledo et al.
(2016MNRAS.456.2406R 2016MNRAS.456.2406R)
25- 27 I3 Msun e_Mass ? Error on Mass
29- 32 F4.1 K Tdust ? Dust temperature obtained from the density
and temperature mass computed by
Rebolledo et al. (2016MNRAS.456.2406R 2016MNRAS.456.2406R)
34- 36 F3.1 K e_Tdust ? Error on Tdust
38- 41 F4.2 pc Rad ? Radius from Rebolledo et al.
(2016MNRAS.456.2406R 2016MNRAS.456.2406R)
43- 46 F4.2 pc e_Rad ? Error on Rad
48- 52 F5.1 10+4cm-3 rho ? Density from Rebolledo et al.
(2016MNRAS.456.2406R 2016MNRAS.456.2406R)
54- 57 F4.1 10+4cm-3 e_rho ? Error on rho
59 I1 --- PAsym ? Profile asymmetry (1)
--------------------------------------------------------------------------------
Note (1): Asymmetry in the line profiles as follows:
1 = HCO+ asymmetry, where no other molecule was detected
2 = Other molecules were detected, but only HCO+ shows asymmetry
3 = More than one molecule shows asymmetry
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 13-Jul-2022