J/A+A/656/A146 HCN and CN emission in Serpens Main region (Mirocha+, 2021)
Signatures of UV radiation in low-mass protostars.
I. Origin of HCN and CN emission in the Serpens Main region.
Mirocha A., Karska A., Gronowski M., Kristensen L.E., Tychoniec L.,
Harsono D., Figueira M., Gladkowski M., Zoltowski M.
<Astron. Astrophys. 656, A146 (2021)>
=2021A&A...656A.146M 2021A&A...656A.146M (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Molecular data ; Spectroscopy
Keywords: stars: protostars - ISM: jets and outflows - ISM: molecules -
ISM: individual objects: Serpens Main - stars: formation -
astrochemistry
Abstract:
Ultraviolet radiation (UV) influences the physics and chemistry of
star-forming regions, but its properties and significance in the
immediate surroundings of low-mass protostars are still poorly
understood. We aim to extend the use of the CN/HCN ratio, already
established for high-mass protostars, to the low-mass regime to trace
and characterize the UV field around low-mass protostars on ∼0.6x0.6pc
scales. The spatial distribution of HCN and CS are well-correlated
with CO 6-5 emission that traces outflows. The CN emission is extended
from the central protostars to their immediate surroundings also
tracing outflows, likely as a product of HCN photodissociation. The
ratio of CN to HCN total column densities ranges from ∼1 to 12
corresponding to G0∼101-103 for gas densities and temperatures
typical for outflows of low-mass protostars. UV radiation associated
with protostars and their outflows is indirectly identified in a
significant part of the Serpens Main low-mass star-forming region. Its
strength is consistent with the values obtained from the OH and H2O
ratios observed with Herschel and compared with models of
UV-illuminated shocks. From a chemical viewpoint, the CN to HCN ratio
is an excellent tracer of UV fields around low- and intermediate-mass
star-forming regions.
Description:
We present 5'x 5' maps of the Serpens Main Cloud encompassing 10
protostars observed with the EMIR receiver at the IRAM 30m telescope
in CN 1-0, HCN 1-0, CS 3-2, and some of their isotopologues. The
radiative-transfer code RADEX and the chemical model Nahoon are used
to determine column densities of molecules, gas temperature and
density, and the UV field strength, G0.
Objects:
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RA (2000) DE Designation(s)
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18 29 49.63 +01 15 21.9 Ser SSM 1 = NAME Serpens SMM 1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 100 6 List of fits files
fits/* . 6 Individial fits files
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Nx Number of pixels along X-axis
7- 12 I6 --- Ny Number of pixels along Y-axis
14- 25 E12.6 Hz bFreq Lower value of frequency interval
27- 37 E11.6 Hz BFreq Lower value of frequency interval
39- 46 F8.1 Hz dFreq Frequency resolution
48- 53 I6 Kibyte size Size of FITS file
55- 65 A11 --- FileName Name of FITS file, in subdirectory fits
67-100 A34 --- Title Title of the FITS file
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History:
From Mirocha Agnieszka, mirochagnieszka(at)gmail.com
Acknowledgements:
We thank the anonymous referee for a careful reading
of the manuscript and many constructive comments. A.M., A.K., M.G.,
and M.A. acknowledge support from the Polish National Science Center
grant 2016/21/D/ST9/01098. A.K. also acknowledges support from the
First TEAM grant of the Foundation for Polish Science No.
POIR.04.04.00-00-5D21/18-00 and the hospitality of the StarPlan group
in the University of Copenhagen dur- ing the manuscript preparation.
The research of LEK is supported by a research grant (19127) from
VILLUM FONDEN. DH acknowledges support from the EACOA Fellowship from
the East Asian Core Observatories Association. M.A. acknowledges
financial support from the European Research Council (Consol- idator
Grant COLLEXISM, grant agreement 811363), the Institut Universitaire
de France, and the Programme National 'Physique et Chimie du Milieu
Interstellaire' (PCMI) of CNRS/INSU with INC/INP cofunded by CEA
and CNES. M.F. acknowledge support from the Polish National Science
Center grant UMO- 2018/30/M/ST9/00757. This article has been supported
by the Polish National Agency for Academic Exchange under Grant No.
PPI/APM/2018/1/00036/U/001. Article number, page 14 of 32. The
research has made use of data from the Herschel Gould Belt survey
(HGBS) project (http://gouldbelt-herschel.cea.fr). The HGBS is a
Herschel Key Pro- gramme jointly carried out by SPIRE Specialist
Astronomy Group 3 (SAG 3), scientists of several institutes in the
PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU
Leuven, MPIA Heidelberg), and scientists of the Herschel Science
Center (HSC).
(End) Patricia Vannier [CDS] 01-Dec-2021