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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 (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) and Kramer et al. (2011EAS....52..107K). More than 1000 H II regions can be resolved by the Hα observations; Courtes et al. (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: ---------------------------------------------------------- RA (ICRS) DE Designation(s) ---------------------------------------------------------- 01 33 50.90 +30 39 35.8 M33 = NAME Triangulum Galaxy ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 18 396 The Hα rotation curve of M33
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
Bytes Format Units Label Explanations
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
History: From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 12-Dec-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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