THE WEAK CARBON MONOXIDE EMISSION IN AN EXTREMELY METAL-POOR GALAXY, SEXTANS A

Yong Shi; Junzhi Wang; Yu Gao; Lee Armus; George Helou; Qiusheng Gu; Sabrina Stierwalt; Zhiyu Zhang

doi:10.1088/2041-8205/804/1/L11

THE WEAK CARBON MONOXIDE EMISSION IN AN EXTREMELY METAL-POOR GALAXY, SEXTANS A

Yong Shi^*, Junzhi Wang, Yu Gao, Lee Armus, George Helou, Qiusheng Gu, Sabrina Stierwalt, Zhiyu Zhang

^*Corresponding author for this work

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

Abstract

Carbon monoxide (CO) is one of the primary coolants of gas and an easily accessible tracer of molecular gas in spiral galaxies, but it is unclear if CO plays a similar role in metal-poor dwarfs. We carried out a deep observation with IRAM 30 m to search for CO emission by targeting the brightest far-IR peak in a nearby extremely metal-poor galaxy, Sextans A, with 7% solar metallicity. A marginal signal of CO J = 1 - 0 emission is seen, which is already faint enough to place a strong constraint on the conversion factor (alpha(CO)) from the CO luminosity to the molecular gas mass that is derived from the spatially resolved dust-mass map. The alpha(CO) is at least seven hundred times the Milky Way value. This indicates that CO emission is exceedingly weak in Sextans A, challenging its role as a coolant in extremely metal-poor galaxies.

Original language	English
Article number	11
Number of pages	4
Journal	Astrophysical Journal Letters
Volume	804
Issue number	1
DOIs	https://doi.org/10.1088/2041-8205/804/1/L11
Publication status	Published - 1 May 2015

Keywords / Materials (for Non-textual outputs)

galaxies: dwarf
galaxies: ISM
submillimeter: ISM
CO-TO-H-2 CONVERSION FACTOR
STAR-FORMATION
LOW-METALLICITY
MOLECULAR GAS
DUST
MASS
CLOUDS
CO

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10.1088/2041-8205/804/1/L11

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title = "THE WEAK CARBON MONOXIDE EMISSION IN AN EXTREMELY METAL-POOR GALAXY, SEXTANS A",

abstract = "Carbon monoxide (CO) is one of the primary coolants of gas and an easily accessible tracer of molecular gas in spiral galaxies, but it is unclear if CO plays a similar role in metal-poor dwarfs. We carried out a deep observation with IRAM 30 m to search for CO emission by targeting the brightest far-IR peak in a nearby extremely metal-poor galaxy, Sextans A, with 7% solar metallicity. A marginal signal of CO J = 1 - 0 emission is seen, which is already faint enough to place a strong constraint on the conversion factor (alpha(CO)) from the CO luminosity to the molecular gas mass that is derived from the spatially resolved dust-mass map. The alpha(CO) is at least seven hundred times the Milky Way value. This indicates that CO emission is exceedingly weak in Sextans A, challenging its role as a coolant in extremely metal-poor galaxies.",

keywords = "galaxies: dwarf, galaxies: ISM, submillimeter: ISM, CO-TO-H-2 CONVERSION FACTOR, STAR-FORMATION, LOW-METALLICITY, MOLECULAR GAS, DUST, MASS, CLOUDS, CO",

author = "Yong Shi and Junzhi Wang and Yu Gao and Lee Armus and George Helou and Qiusheng Gu and Sabrina Stierwalt and Zhiyu Zhang",

year = "2015",

month = may,

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doi = "10.1088/2041-8205/804/1/L11",

language = "English",

volume = "804",

journal = "Astrophysical Journal Letters",

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T1 - THE WEAK CARBON MONOXIDE EMISSION IN AN EXTREMELY METAL-POOR GALAXY, SEXTANS A

AU - Shi, Yong

AU - Wang, Junzhi

AU - Gao, Yu

AU - Armus, Lee

AU - Helou, George

AU - Gu, Qiusheng

AU - Stierwalt, Sabrina

AU - Zhang, Zhiyu

PY - 2015/5/1

Y1 - 2015/5/1

N2 - Carbon monoxide (CO) is one of the primary coolants of gas and an easily accessible tracer of molecular gas in spiral galaxies, but it is unclear if CO plays a similar role in metal-poor dwarfs. We carried out a deep observation with IRAM 30 m to search for CO emission by targeting the brightest far-IR peak in a nearby extremely metal-poor galaxy, Sextans A, with 7% solar metallicity. A marginal signal of CO J = 1 - 0 emission is seen, which is already faint enough to place a strong constraint on the conversion factor (alpha(CO)) from the CO luminosity to the molecular gas mass that is derived from the spatially resolved dust-mass map. The alpha(CO) is at least seven hundred times the Milky Way value. This indicates that CO emission is exceedingly weak in Sextans A, challenging its role as a coolant in extremely metal-poor galaxies.

AB - Carbon monoxide (CO) is one of the primary coolants of gas and an easily accessible tracer of molecular gas in spiral galaxies, but it is unclear if CO plays a similar role in metal-poor dwarfs. We carried out a deep observation with IRAM 30 m to search for CO emission by targeting the brightest far-IR peak in a nearby extremely metal-poor galaxy, Sextans A, with 7% solar metallicity. A marginal signal of CO J = 1 - 0 emission is seen, which is already faint enough to place a strong constraint on the conversion factor (alpha(CO)) from the CO luminosity to the molecular gas mass that is derived from the spatially resolved dust-mass map. The alpha(CO) is at least seven hundred times the Milky Way value. This indicates that CO emission is exceedingly weak in Sextans A, challenging its role as a coolant in extremely metal-poor galaxies.

KW - galaxies: dwarf

KW - galaxies: ISM

KW - submillimeter: ISM

KW - CO-TO-H-2 CONVERSION FACTOR

KW - STAR-FORMATION

KW - LOW-METALLICITY

KW - MOLECULAR GAS

KW - DUST

KW - MASS

KW - CLOUDS

KW - CO

U2 - 10.1088/2041-8205/804/1/L11

DO - 10.1088/2041-8205/804/1/L11

M3 - Article

SN - 2041-8205

VL - 804

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 1

M1 - 11

ER -

THE WEAK CARBON MONOXIDE EMISSION IN AN EXTREMELY METAL-POOR GALAXY, SEXTANS A

Abstract

Keywords / Materials (for Non-textual outputs)

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