J/MNRAS/452/1412 Dust and SSP-stellar parameters of M82 (Hutton+, 2015)
Variations of the dust properties of M82 with galactocentric distance.
Hutton S., Ferreras I., Yershov V.
<Mon. Not. R. Astron. Soc., 452, 1412-1420 (2015)>
=2015MNRAS.452.1412H 2015MNRAS.452.1412H (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Interstellar medium ; Populations, stellar ;
Extinction ; Stars, ages ; Photometry, ultraviolet
Keywords: supernovae: individual: SN 2014J - dust, extinction -
galaxies: individual: M82 - galaxies: ISM - galaxies: starburst -
galaxies: stellar content
Abstract:
We use near ultraviolet and optical photometry to investigate the dust
properties in the nearby starburst galaxy M82. By combining imaging
from the Swift/UVOT instrument and optical data from the Sloan Digital
Sky Survey, we derive the extinction curve parametrized by the
standard RV factor, and the strength of the NUV 2175 Å feature -
quantified by a parameter B - out to projected galactocentric distances
of 4 kpc. Our analysis is robust against possible degeneracies from
the properties of the underlying stellar populations. Both B and
RV correlate with galactocentric distance, revealing a systematic
trend of the dust properties. Our results confirm previous findings
that dust in M82 is better fitted by a Milky Way standard extinction
curve, in contrast to a Calzetti law. We find a strong correlation
between RV and B, towards a stronger NUV bump in regions with higher
RV, possibly reflecting a distribution with larger dust grain sizes.
The data we use were taken before SN2014J, and therefore can be used
to probe the properties of the interstellar medium before the event.
Our RV values around the position of the supernova are significantly
higher than recent measurements post-SN2014J (RV∼1.4). This result is
consistent with a significant change in the dust properties after the
supernova event, either from disruption of large grains or from the
contribution by an intrinsic circumstellar component. Intrinsic variations
among supernovae not accounted for could also give rise to this mismatch.
Description:
We use the same data set as in Hutton et al. (2014MNRAS.440..150H 2014MNRAS.440..150H). In
a nutshell, deep NUV images were retrieved from the HEASARC archive of
Swift/UVOT. The Ultraviolet/Optical Telescope (UVOT; Roming et al.
2005SSRv..120...95R 2005SSRv..120...95R) is a 30 cm instrument working as a photon counter,
with three passbands in the NUV region, straddling the position of the
2175Å bump. We refer the reader to Poole et al. (2008MNRAS.383..627P 2008MNRAS.383..627P)
and Breeveld et al. (2010MNRAS.406.1687B 2010MNRAS.406.1687B) for details of the properties,
mode of operation and data reduction procedure of UVOT imaging. We
retrieved imaging data of M82 with total exposure times of 10.2, 13.9 and
8.7 ks in the UVW2, UVM2, and UVW1 passbands, respectively. The data were
taken between 2008 and 2012, therefore our photometry corresponds to the
galaxy before the SN2014J event. In addition to the UVOT data, we retrieved
optical images from the SDSS DR8 server (Aihara et al. 2011ApJS..193...29A 2011ApJS..193...29A).
Objects:
---------------------------------------------
RA (ICRS) DE Designation(s)
---------------------------------------------
09 55 52.43 +69 40 46.9 M82 = NGC 3034
---------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 73 351 Dust and SSP-stellar parameters of M82
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See also:
J/AJ/121/768 : BVIJH photometry of M82 (de Grijs+, 2001)
J/ApJ/619/270 : Young super star clusters in the starburst of M82 (Melo+, 2005)
J/ApJ/679/404 : Star clusters in M82 (Mayya+, 2008)
J/ApJ/766/20 : HST photometry of star clusters in M82 (Lim+, 2013)
J/ApJS/216/6 : Opt-NIR HST photometry of cluster candidates in M82 (Li+, 2015)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000) (1)
11- 18 F8.5 deg DEdeg Declination in decimal degrees (J2000) (1)
20- 24 F5.3 kpc DeltaR Projected galactocentric distance ΔR
26- 30 F5.3 --- Rv Total-to-selective attenuation ratio RV
32- 36 F5.3 --- e_Rv Uncertainty in Rv (2)
38- 42 F5.3 --- B NUV bump strength
44- 48 F5.3 --- e_B Uncertainty in B (2)
50- 54 F5.3 mag E(B-V) Colour excess
56- 60 F5.3 mag e_E(B-V) Uncertainty in E(B-V) (2)
62- 67 F6.3 [Gyr] logAge Base-10 logarithm of the simple stellar
population (SSP) age
69- 73 F5.3 [Gyr] e_logAge Uncertainty in logAge (2)
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Note (1): Each coordinate represents the position of the centre of a circular
aperture with R=5arcsec.
Note (2): Uncertainties are quoted at the 1σ level.
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 19-Dec-2017