J/A+A/576/A58 Integral Field 560-680nm observation of M81 (Ricci+, 2015)
A hot bubble at the centre of M81.
Ricci T.V., Steiner J.E., Giansante L.
<Astron. Astrophys. 576, A58 (2015)>
=2015A&A...576A..58R 2015A&A...576A..58R
ADC_Keywords: Galaxies, nearby ; Spectroscopy
Keywords: techniques: imaging spectroscopy - galaxies: nuclei -
galaxies: individual: M81 - ISM: jets and outflows - ISM: bubbles -
galaxies: active
Abstract:
M81 has the nearest active nucleus with broad Hα emission. A
detailed study of this galaxy's centre is important for understanding
the innermost structure of the AGN phenomenon.
Our goal is to seek previously undetected structures using additional
techniques to reanalyse a data cube obtained with the GMOS-IFU
installed on the Gemini North telescope (Schnorr Muller et al.,
2011MNRAS.413..149S 2011MNRAS.413..149S).
We analysed the data cube using techniques of noise reduction, spatial
deconvolution, starlight subtraction, PCA Tomography and comparison
with HST images.
We identified a hot bubble with T>43500K that is associated with
strong emission of [NII]λ5755Å and large
[OI]λ6300/Hα ratio, as well as with a bluish continuum,
surrounded by a thin shell of Hα+[NII] emission. We also
reinterpret the outflow found by Schnorr Muller et al.
(2011MNRAS.413..149S 2011MNRAS.413..149S) showing that the blueshifted cone nearly
coincides with the radio jet, as expected.
We interpret the hot bubble as likely to be caused by post starburst
events that left one or more clusters of young stars, somewhat similar
to the ones found at the centre of the Milky Way, like the Arches and
the IRS 16 clusters. Shocked structures from combined young stellar
winds or supernova remnants are probably the cause of this hot gas and
the low ionization emission.
Description:
Data cube of M81 observed with Gemini-North telescope using GMOS-IFU.
The data cube has a field-of-view of 5x7-arcsec2 and a spectral
range of 5601-6802Å. The spatial resolution is 0.89-arcsec. Full
details of the data reduction are explained in section 2 of the paper.
Objects:
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RA (2000) DE Designation(s)
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09 55 33.2 +69 03 55 M81 = NGC 3031
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 103 1 Information on datacude file
gmosifu.fits 2880 22596 Reduced data cube of M81 (560-680nm)
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx [121] Number of pixels along X-axis
24- 25 I2 --- Ny [76] Number of pixels along Y-axis
27- 30 I4 --- Nz [1769] Number of wavelength planes
32- 38 F7.2 0.1nm lam.min [5601.14] Lower value of wavelength interval
40- 46 F7.2 0.1nm lam.max [6801.89] Upper value of wavelength interval
48- 55 F8.6 0.1nm dlam [0.679154] Spectral resolution
57- 61 I5 Kibyte size [63554] Size of FITS file
63- 78 A16 --- FileName Name of the FITS datacude
80-103 A24 --- Title Title of the file
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Acknowledgements:
Tiago Ricci, tvr.astro(at)gmail.com
(End) Tiago Ricci [IAG-USP, Brazil], Patricia Vannier [CDS] 17-Feb-2015