J/MNRAS/527/10668 JWST observations of M33 (Peltonen+, 2024)
JWST reveals star formation across a spiral arm in M33.
Peltonen J., Rosolowsky E., Williams T.G., Koch E.W., Dolphin A.,
Chastenet J., Dalcanton J.J., Ginsburg A., Johnson L.C., Leroy A.K.,
Richardson T., Sandstrom K.M., Sarbadhicary S.K., Smercina A., Wainer T.,
Williams B.F.
<Mon. Not. R. Astron. Soc. 527, 10668 (2024)>
=2024MNRAS.52710668P 2024MNRAS.52710668P (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; YSOs ; Photometry, millimetric/submm
Keywords: stars: protostars - ISM: clouds - galaxies: individual: M33
Abstract:
Young stellar objects (YSOs) are the gold standard for tracing star
formation in galaxies but have been unobservable beyond the Milky Way
and Magellanic Clouds. But that all changed when the JWST was
launched, which we use to identify YSOs in the Local Group galaxy M33,
marking the first time that individual YSOs have been identified at
these large distances. We present Mid-Infrared Instrument (MIRI)
imaging mosaics at 5.6 and 21um that cover a significant portion of
one of M33's spiral arms that has existing panchromatic imaging from
the Hubble Space Telescope and deep Atacama Large
Millimeter/submillimeter Array CO measurements. Using these MIRI and
Hubble Space Telescope images, we identify point sources using the new
DOLPHOT MIRI module. We identify 793 candidate YSOs from cuts based on
colour, proximity to giant molecular clouds (GMCs), and visual
inspection. Similar to Milky Way GMCs, we find that higher mass GMCs
contain more YSOs and YSO emission, which further show YSOs identify
star formation better than most tracers that cannot capture this
relationship at cloud scales. We find evidence of enhanced star
formation efficiency in the southern spiral arm by comparing the YSOs
to the molecular gas mass.
Description:
Under JWST GO program 2128, we observed M33 using the MIRI instrument
onboard JWST as the primary camera operated in imaging mode. We
observed a 5x5 tile mosaic in the galaxy that covers a
0.20°x0.16° region on the sky, which projects to an area of
5.5kpc2. The survey is centred on RA=23.4376° and
Dec=30.5813°, covering a significant portion of one of M33's
spiral arms.
We observed in the 21um (F2100W) and 5.6um (F560W) filters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 56 793 M33 young stellar object candidates
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 F9.6 deg RAdeg [23.37/23.54] Right ascension (ICRS)
11- 19 F9.6 deg DEdeg [30.52/30.65] Declination (ICRS)
21- 28 F8.2 uJy F21um [5.0/40218.54] JWST MIRI 21 micron band flux,
MIRI filter F2100W
30- 33 F4.2 uJy e_F21um Uncertainty in F21um
35- 40 F6.2 uJy F5.6um [2.04/775.58] JWST MIRI 5.6 micron band flux,
MIRI filter F560W
42- 45 F4.2 uJy e_F5.6um Uncertainty in F5.6um
47- 51 F5.2 uJy F1.6um [0.67/26.82] HST 1.6 micron band flux,
HST filter F160W
53- 56 F4.2 uJy e_F1.6um [0.02/0.08] Uncertainty in F1.6um
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Acknowledgements:
Joshua Peltonen, peltonen(at)ualberta.ca
(End) Joshua Peltonen [Univ. Alberta], Patricia Vannier [CDS] 10-Jan-2024