J/MNRAS/449/4048 The Hα rotation curve of M33 (Kam+, 2015)
Kinematics and mass modelling of M33: Hα observations.
Kam Z.S., Carignan C., Chemin L., Amram P., Epinat B.
<Mon. Not. R. Astron. Soc., 449, 4048-4070 (2015)>
=2015MNRAS.449.4048K 2015MNRAS.449.4048K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Galaxies, rotation ; Interferometry ;
Rotational velocities
Keywords: techniques: interferometric - ISM: bubbles - HII regions -
galaxies: individual: M33 - galaxies: ISM -
galaxies: kinematics and dynamics - dark matter
Abstract:
As part of a long-term project to revisit the kinematics and dynamics
of the large disc galaxies of the Local Group, we present the first
deep, wide-field (∼42arcmin x 56arcmin) 3D-spectroscopic survey of
the ionized gas disc of Messier 33. Fabry-Perot interferometry has
been used to map its Hα distribution and kinematics at unprecedented
angular resolution (~<3 arcsec) and resolving power (∼12600), with
the 1.6 m telescope at the Observatoire du Mont Megantic. The ionized
gas distribution follows a complex, large-scale spiral structure,
unsurprisingly coincident with the already-known spiral structures of
the neutral and molecular gas discs. The kinematical analysis of the
velocity field shows that the rotation centre of the Hα disc is
distant from the photometric centre by ∼168 pc (sky-projected distance)
and that the kinematical major-axis position angle and disc inclination
are in excellent agreement with photometric values. The Hα
rotation curve agrees very well with the HI rotation curves for
0<R<6.5 kpc, but the Hα velocities are 10-20 km/s higher for
R>6.5 kpc. The reason for this discrepancy is not well understood. The
velocity dispersion profile is relatively flat around 16 km/s, which
is at the low end of velocity dispersions of nearby star-forming
galactic discs. A strong relation is also found between the Hα
velocity dispersion and the Hα intensity. Mass models were
obtained using the Hα rotation curve but, as expected, the dark
matter halo's parameters are not very well constrained since the
optical rotation curve only extends out to 8 kpc.
Description:
This study presents Fabry-Perot mapping of M33 obtained at the Observatoire
du mont Megantic (OMM). Relano et al. (2013, J/A+A/552/A140) have studied
the spectral energy distribution of the H II regions of M33 and the
star formation rate and star formation efficiency have been investigated
by Gardan et al. (2007A&A...473...91G 2007A&A...473...91G) and Kramer et al.
(2011EAS....52..107K 2011EAS....52..107K). More than 1000 H II regions can be resolved by
the Hα observations; Courtes et al. (1987A&A...174...28C 1987A&A...174...28C) gave a
catalogue of 748 H II regions. Observing those regions allows us to
derive the ionized gas (optical) kinematics of M33. Determination of
the M33 kinematics with a spatial resolution ~<3 arcsec (∼12 pc) using
the H{spectra} velocity field and the derivation of an accurate RC in
the inner parts are the main goals of this paper.
The observations took place at the 1.6-m telescope of the OMM, Quebec,
in 2012 September. A scanning FP etalon interferometer has been used
during the observations with the device IXON888, a commercial Andor
EM-CCD camera of 1024 pixelsx1024 pixels.
Objects:
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RA (ICRS) DE Designation(s)
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01 33 50.90 +30 39 35.8 M33 = NAME Triangulum Galaxy
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 18 396 The Hα rotation curve of M33
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See also:
J/AJ/110/2739 : H-alpha emitting regions in M33 (Calzetti+ 1995)
J/PASP/111/685 : HII regions of M33. II. (Hodge+, 1999)
J/AJ/154/41 : Rotational velocities of M33 (Kam+, 2017)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 5 F5.2 arcmin Rad Radius
7- 9 I3 km/s Vrot Rotation velocity
11- 12 I2 km/s e_Vrot Uncertainty in Vrot
14- 15 I2 km/s sigma Velocity dispersion
17- 18 I2 km/s e_sigma Uncertainty in sigma
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 12-Dec-2017