J/ApJ/826/209 IRX-β relation of HII regions in NGC628 (Ye+, 2016)
IRX-β relation of star-forming regions in NGC 628 based on integral field
spectroscopy.
Ye C., Zou H., Lin L., Lian J., Hu N., Kong X.
<Astrophys. J., 826, 209-209 (2016)>
=2016ApJ...826..209Y 2016ApJ...826..209Y (SIMBAD/NED BibCode)
ADC_Keywords: Spectroscopy ; Ultraviolet ; Infrared sources ; Galaxies, nearby ;
H II regions
Keywords: dust, extinction; galaxies: star formation; infrared: galaxies;
ultraviolet: galaxies
Abstract:
It has been found that the infrared-to-ultraviolet luminosity ratio
(IRX) and ultraviolet spectral slope (β) have a tight correlation
in starburst galaxies, while in normal galaxies the relation is
deviated and has a much larger scatter. Star formation regions are
much simpler in both morphology and physical properties than galaxies,
so their photometric and spectroscopic properties are more easily and
accurately determined. We have used the integral field spectroscopy
and multiband photometric images to study the IRX-β relation of
HII regions in a nearby galaxy, NGC 628. There are obvious
correlations between the Dn (4000), stellar population age, star
formation rate, especially Hα equivalent width EW(Hα), and
deviation distance dp from the starburst IRX-β relation.
However, there is little correlation between the Balmer decrement,
metallicity, and dp. It is much more complicated than expected, so
that we cannot introduce a single second parameter to describe the
scatter and deviation of the HII region IRX-β relation.
Description:
NGC 628 has been observed by the PPAK IFS Nearby Galaxies Survey
(PINGS) performed by the 3.5m telescope of the Calar Alto Observatory.
The IFU provides a sampling of 2.7", an optical wavelength range of
3700-7000Å with a spectral resolution of ∼8Å. The final data set
comprises 11094 individual spectra, and the typical spatial resolution
is about 3.5"-4". The slice image at the Hα wavelength is used
to determine HII regions.
FUV and near-UV (NUV) images of NGC 628 were taken by the Galaxy
Evolution Explorer (GALEX), which are centered at wavelengths of 1516
and 2267Å. IR images were taken by Spitzer IRAC (3.6um, 8.0um) and
MIPS (24um). The spatial resolutions of UV and IR images are 4.3",
5.3", 1.9", 2.8", and 6.4", respectively. We obtain these images from
the data release website of Local Volume Legacy (LVL) survey DR5
(Dale+, 2009, J/ApJ/703/517;
http://irsa.ipac.caltech.edu/data/SPITZER/LVL/).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 104 283 Position and photometry of the HII regions
table2.dat 126 143 The emission line fluxes and properties derived
from spectra of HII regions
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See also:
II/312 : GALEX-DR5 (GR5) sources from AIS and MIS (Bianchi+ 2011)
J/ApJ/806/16 : CHemical Abundances of Spirals (CHAOS) I. NGC628 (Berg+, 2015)
J/A+A/559/A114 : Updated O3N2 and N2 abundance indicators (Marino+, 2013)
J/A+A/546/A2 : Spectroscopy of HII regions in nearby gal. (Sanchez+, 2012)
J/A+A/545/A43 : HII regions in NGC 628 and NGC 6946 (Cedres+, 2012)
J/ApJ/757/52 : UV and IR observations for SINGS galaxies. I. (Mao+, 2012)
J/ApJS/192/6 : A GALEX UV imaging survey of nearby galaxies (Lee+, 2011)
J/ApJ/703/517 : The Spitzer Local Volume Legacy: IR photometry (Dale+, 2009)
J/ApJ/701/1965 : Radial dust properties of SINGS galaxies (Munoz-Mateos+, 2009
J/ApJS/178/247 : Hα and [NII] survey in local 11 Mpc (Kennicutt+, 2008)
J/ApJ/671/333 : Aperture photometry in NGC 5194 (Kennicutt+, 2007)
J/A+A/466/905 : HII regions in NGC 628 (Fathi+, 2007)
J/ApJ/633/871 : Positions and photometry of HII knots in M51 (Calzetti+, 2005)
J/AJ/120/1306 : NGC 628 H II regions (Lelievre+, 2000)
J/A+AS/119/499 : NGC 628 and companions photometric distances (Sharina+ 1996)
http://calmecac.inaoep.mx/~frosales/pings : PINGS home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Running index number
5- 12 F8.5 deg RAdeg [24.12/24.22] Right Ascension (J2000)
14- 21 F8.5 deg DEdeg [15.73/15.85] Declination (J2000)
23- 28 F6.3 [10-7W] logLFUV [38.3/40.7] log GALEX FUV band luminosity;
in erg/s units
30- 34 F5.3 [10-7W] e_logLNUV [0.002/0.2] Uncertainty in logLNUV
36- 41 F6.3 [10-7W] logLNUV [38.2/40.6] log GALEX NUV band luminosity;
in erg/s units
43- 47 F5.3 [10-7W] e_logLFUV [0.006/0.4] Uncertainty in logLFUV
49- 54 F6.3 [10-7W] logLIR [38.7/41] log IR (8 and 24um) luminosity;
in erg/s units
56- 60 F5.3 [10-7W] e_logLIR [0.004/0.3] Uncertainty in logLIR
62- 67 F6.3 --- IRX [-0.3/1.2] Infrared-to-ultraviolet
luminosity ratio
69- 73 F5.3 --- e_IRX [0.03/1.6] Uncertainty in IRX
75- 80 F6.3 --- beta [-2.1/0.7] Ultraviolet spectral slope
82- 86 F5.3 --- e_beta [0.03/2] Uncertainty in beta
88- 93 F6.3 --- dp [-0.5/1.6] Deviation distance dp from the
starburst IRX-β relation
95- 99 F5.3 kpc2 Area [0.01/1] H II area
101-104 A4 --- n_Seq Note on Seq (1)
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Note (1): Note as follows:
STAR = regions near the foreground stars (20 sources);
EDGE = regions on the FoV edge (10 sources);
HII = normal HII regions (153 sources).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Running index number
5- 10 F6.3 [10-7W] logLHb [36.1/38.5] log Hβ line luminosity
12- 16 F5.3 [10-7W] e_logLHb Uncertainty in logLHb
18- 23 F6.3 [10-7W] logLO3 [35.7/38.3] log [O III] line luminosity
25- 29 F5.3 [10-7W] e_logLO3 Uncertainty in logLO3
31- 36 F6.3 [10-7W] logLHa [36.9/39.1] log Hα line luminosity
38- 42 F5.3 [10-7W] e_logLHa Uncertainty in logLHa
44- 49 F6.3 [10-7W] logLN2 [36.4/38.6] log [N II] line luminosity
51- 55 F5.3 [10-7W] e_logLN2 Uncertainty in logLN2
57- 64 F8.3 0.1nm EW [2/1183]? Hα equivalent width;
Angstroms (1)
66- 71 F6.3 0.1nm e_EW [0.2/16] Uncertainty in EW
73- 77 F5.3 [-] N2 [8.3/8.6] The 12+logO/H number abundance
from N2 indicator
79- 83 F5.3 [-] e_N2 Uncertainty in N2
85- 89 F5.3 [-] O3N2 [8.2/8.8] The 12+logO/H number abundance
from O3N2 indicator
91- 95 F5.3 [-] e_O3N2 Uncertainty in O3N2
97-102 F6.3 [Msun/yr] logSFR [-4.2/-2] log Star Formation Rate
104-108 F5.3 [Msun/yr] e_logSFR Uncertainty in logSFR
110-114 F5.3 --- Dn4000 [0.8/2] The Dn(4000) spectral index
116-120 F5.3 --- e_Dn4000 Uncertainty in Dn4000
122-126 F5.3 [yr] logAge [6.3/10] log age (2)
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Note (1): A blank indicates a NaN value.
Note (2): The signal-to-noise ratios (S/Ns) of our HII spectra are larger
than 8, so the age uncertainty is about 0.01-0.08dex as estimated
by Cid Fernandes et al. (2005MNRAS.358..363C 2005MNRAS.358..363C).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Oct-2016