NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2018-10-23 T12:01:49 PDT
Help | Comment | NED Home

For refcode 2006ApJ...644L..29V:
Retrieve 2 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
2006ApJ...644L..29V Detection of [O I] {lambda}6300 and Other Diagnostic Emission Lines in the Diffuse Ionized Gas of M33 with Gemini-North E. S. Voges and R. A. M. Walterbos Abstract. We present spectroscopic observations of diffuse ionized gas (DIG) in M33 near the H II region NGC 604. We present the first detection of [O i] {lambda}6300 in the DIG of M33, one of the critical lines for distinguishing photoionization from shock ionization models. We measure [O i]/H{alpha} in the range of 0.04 -- 0.10 and an increase in this ratio with decreasing emission measure. Our measurements of [S II]/H{alpha} and [N II]/H{alpha} also rise with decreasing emission measure, while our [O III]/H{beta} measurements remain fairly constant. We have one tentative detection of He i in the region of brightest emission measure, with a ratio of He i/H{alpha} = 0.033 +/- 0.019, indicating that the helium is at least partially ionized. We compare our observed emission-line ratios to photoionization models and find that field star ionization models do not fit our data well. Leaky H II region models are consistent with our data, without the need to invoke additional ionization mechanisms to fit our [O i] or [O III] measurements. The closest large H II region is NGC 604 and is therefore a likely candidate for the source of the ionizing photons for the gas in this region. Key words: Galaxies: Individual: M33, Galaxies: ISM
Retrieve 2 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home