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J/A+A/602/A85         SN 1998bw MUSE datacube                  (Kruehler+, 2017)

Hot gas around SN 1998bw: Inferring the progenitor from its environment. Kruehler T., Kuncarayakti H., Schady P., Anderon J.P., Galbany L., Gensior J. <Astron. Astrophys. 602, A85 (2017)> =2017A&A...602A..85K (SIMBAD/NED BibCode)
ADC_Keywords: Gamma rays Keywords: galaxies: ISM - galaxies: abundances - galaxies: star formation - gamma-ray burst: general - gamma-ray burst: individual: GRB 980425 Abstract: Spatially resolved spectroscopy of the environments of explosive transients carries detailed information about the physical properties of the stellar population that gave rise to the explosion, and thus the progenitor itself. Here, we present new observations of ESO184-G82, the galaxy hosting the archetype of the γ-ray burst/supernova connection, GRB 980425/SN 1998bw, obtained with the integral field spectrograph MUSE mounted at the Very Large Telescope. These observations have yielded detailed maps of emission-line strength for various nebular lines along with physical parameters such as dust extinction, stellar age, and oxygen abundance on spatial scales of 160pc. The immediate environment of GRB 980425 is young 5-8Myr) and consistent with a mildly extinguished (AV∼0.1mag) progenitor of zero-age main-sequence mass between 25 M and 40 M and an oxygen abundance 12+log(O=H)∼8.2 (Z∼0.3Z), which is slightly lower than that of an integrated measurement of the whole galaxy (12+log(O=H)∼8.3) and a prominent nearby HII region (12+log(O/H)∼8.4). This region is significantly younger than the explosion site, and we argue that a scenario in which the GRB progenitor formed in this environment and was subsequently ejected appears very unlikely. We show that empirical strong-line methods based on [O iii] and/or [N ii] are inadequate to produce accurate maps of oxygen abundance at the level of detail of our MUSE observation as these methods strongly depend on the ionization state of the gas. The metallicity gradient in ESO184-G82 is -0.06dex/kpc, indicating that the typical offsets of at most few kpc for cosmological GRBs on average have a small impact on oxygen abundance measurements at higher redshift. Description: The ESO184-G82 data cube (SN1998bwastphotcube.fits) is a multi-dimensional fits file with a primary header and two extensions: The primary header contains only the fits headers. The first fits extension (DATA) contains the observed flux values in units of 10-20erg/cm^2/s/Å. The dimensions of the cube are 320x324x3682 where the first two are celestial coordinates (RA, DEC), and the last one the wavelength coordinate. The second fits extension (STAT) contains the estimated variance in units of 10-40erg-2cm-4s-2Å-2 Objects: ------------------------------------------------- RA (2000) DE Designation(s) ------------------------------------------------- 19 35 03.17 -52 50 46.1 SN1998bw = GRB 980425 ------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 126 2 Information on datacude SN1998bw.fits 2880 1060456 Datacude (2.9G)
Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000) 10- 18 F9.5 deg DEdeg Declination of center (J2000) 20- 22 F3.1 arcsec/pix scale Scale of the image 24- 26 I3 --- Nx Number of pixels along X-axis 28- 30 I3 --- Ny Number of pixels along Y-axis 32- 35 I4 --- Nz Number of slices 37- 43 F7.2 0.1nm blambda Lower value of wavelength interval 45- 51 F7.2 0.1nm Blambda Upper value of wavelength interval 53- 59 F7.5 0.1nm dlambda Wavelenght resolution 61- 67 I7 Kibyte size Size of FITS file 69- 81 A13 --- FileName Name of FITS file 83-126 A44 --- Title Title of the FITS file extension
Acknowledgements: Thomas Kruehler, kruehler(at)mpe.mpg.de
(End) Patricia Vannier [CDS] 18-May-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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