J/AJ/158/229 Properties of FUV bright SFRs in IC 2574 (Mondal+, 2019)
Ultraviolet Imaging Telescope view of dwarf irregular galaxy IC 2574:
is the star formation triggered due to expanding H I shells?
Mondal C., Subramaniam A., George K.
<Astron. J., 158, 229 (2019)>
=2019AJ....158..229M 2019AJ....158..229M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Star Forming Region ; Photometry, ultraviolet
Keywords: Dwarf galaxies - Star formation
Abstract:
Star-forming dwarf galaxies in the local volume are diverse and ideal
test beds to understand the details of star formation in a variety of
environments. Here we present a deep far-UV (FUV) imaging study of the
nearby dwarf irregular galaxy IC 2574 using the Ultraviolet Imaging
Telescope. We identified 419 FUV-bright regions with radii between 15 and
285 pc in the galaxy and found that 28.6% of them are located in H I
shells, 12.6% inside holes, and 60.1% away from the holes. The H I column
density is found to be more than 1021 cm-2 for 82.3% of the identified
regions. Thirty of the 48 H I holes show triggered star formation in their
shells, while 16 holes do not show any related FUV emission. Cross-matching
with Hα emission, we found that 23 holes have both FUV and Hα
emission in their shells, signifying a very recent trigger. Therefore,
star formation in the galaxy has been partly triggered due to the expanding
H I holes, whereas in the majority of the sites, it is driven by other
mechanisms. Irrespective of the location, larger star-forming complexes
were found to have multiple substructures. We report two resolved
components for the remnant cluster of the supergiant shell and estimate
their masses. The star formation rate of IC 2574 is found to be
0.57 M☉/yr, which is slightly higher compared to the average value
of other nearby dwarf irregular galaxies.
Description:
The deep FUV imaging observation of the galaxy IC 2574 was performed
using the UVIT on board the AstroSat satellite (Kumar et al.
2012SPIE.8443E..1NK). The instrument consists of two coaligned telescopes,
one for the FUV (1300-1800 Å) and another for both NUV (2000-3000 Å)
and visible. It has the capability of observing sources simultaneously
in all three available bands. The galaxy IC 2574 was imaged in F148W,
an FUV broadband filter of UVIT. The observations were carried out
with nine orbits of AstroSat.
Objects:
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RA (ICRS) DE Designation(s)
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10 28 23.62 +68 24 43.4 IC 2574 = IRAS 10251+6843
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 62 419 Properties of FUV bright star forming regions
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See also:
J/AJ/136/2563 : HI Nearby Galaxy Survey, THINGS (Walter+, 2008)
J/AJ/144/182 : Stellar groups in IC 2574 (Pellerin+, 2012)
J/AJ/146/46 : Star Formation Rate in nearby galaxies (Karachentsev+, 2013)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Region [1/419] Region number
5- 6 I2 h RAh Hour of Right Ascension (J2000)
8- 9 I2 min RAm Minute of Right Ascension (J2000)
11- 14 F4.1 s RAs Second of Right Ascension (J2000)
16 A1 --- DE- Sign of the Declination (J2000)
17- 18 I2 deg DEd Degree of Declination (J2000)
20- 21 I2 arcmin DEm Arcminute of Declination (J2000)
23- 26 F4.1 arcsec DEs Arcsecond of Declination (J2000)
28- 32 F5.1 pc Rad [13.5/285.7] Radius
34- 37 F4.2 kpc Rgc [0.03/9.79] Galactocentric distance
39- 44 F6.2 10-17W/m2/nm Flux [0.08/143.31] Total FUV flux (1)
46- 50 F5.2 10+28W/pc2 LumDen [1.17/26.59] FUV luminosity density (2)
52- 57 F6.4 Msun/yr/kpc2 SFRDen [0.0238/0.5409] Star Formation Rate density
59- 62 F4.2 10+21/cm2 NHI [0.11/3.83] Average H I column density
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Note (1): In units of 1e-15 erg/s/cm2/Å.
Note (2): In units of 1e+35 erg/s/pc2.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 24-Jan-2020