Hα + [N II] observations of the H II regions in M81

Weipeng Lin, Xu Zhou, David Burstein, Rogier Windhorst, Jiansheng Chen, Wen Ping Chen, Zhaoji Jiang, Xu Kong, Jun Ma, Wei Hsin Sun, Hong Wu, Suijian Xue, Jin Zhu

Research output: Contribution to journalArticle

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Abstract

In a first of a series of studies of the Hα + [N II] emission from nearby spiral galaxies, we present measurements of Hα + [N II] emission from H II regions in M81. Our method uses large-field CCD images and long-slit spectra and is part of the ongoing Beijing-Arizona-Taipei-Connecticut Sky Survey (the BATC survey). The CCD images are taken with the National Astronomical Observatories of China (NAOC) 0.6/0.9 m f/3 Schmidt telescope at the Xinglong Observing Station, using a multicolor filter set. Spectra of 10 of the brightest H II regions are obtained using the NAOC 2.16 m telescope with a Tek 1024 × 1024 CCD. The continua of the spectra are calibrated by flux-calibrated images taken from the Schmidt observations. We determine the continuum component of our Hα + [N II] image via interpolation from the more accurately measured backgrounds (M81 starlight) obtained from the two neighboring (in wavelength) BATC filter images. We use the calibrated fluxes of Hα + [N II] emission from the spectra to normalize this interpolated, continuum-subtracted Hα + [N II] image. We estimate the zero-point uncertainty of the measured Hα + [N II] emission flux to be ∼8%. A catalog of Hα + [N II] fluxes for 456 H II regions is provided, with those fluxes being on a more consistent linear scale than previously available. The logarithmically binned Hα + [N II] luminosity function of H II regions is found to have slope α = -0.70, consistent with previous results (which allowed α = -0.5 to -0.8). From the overall Hα + [N II] luminosity of the H II regions, the star formation rate of M81 is found to be ∼0.68 M yr-1, modulo uncertainty with extinction corrections.

Original languageEnglish (US)
Pages (from-to)1286-1294
Number of pages9
JournalAstronomical Journal
Volume126
Issue number3 1773
DOIs
StatePublished - Sep 2003

Fingerprint

H II regions
charge coupled devices
astronomical observatories
continuums
China
luminosity
image filters
Schmidt telescopes
observatory
filter
spiral galaxies
star formation rate
catalogs
interpolation
slits
extinction
stations
telescopes
slopes
filters

Keywords

  • Galaxies: individual (M81)
  • Galaxies: photometry
  • H II regions

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Lin, W., Zhou, X., Burstein, D., Windhorst, R., Chen, J., Chen, W. P., ... Zhu, J. (2003). Hα + [N II] observations of the H II regions in M81. Astronomical Journal, 126(3 1773), 1286-1294. https://doi.org/10.1086/377519

Hα + [N II] observations of the H II regions in M81. / Lin, Weipeng; Zhou, Xu; Burstein, David; Windhorst, Rogier; Chen, Jiansheng; Chen, Wen Ping; Jiang, Zhaoji; Kong, Xu; Ma, Jun; Sun, Wei Hsin; Wu, Hong; Xue, Suijian; Zhu, Jin.

In: Astronomical Journal, Vol. 126, No. 3 1773, 09.2003, p. 1286-1294.

Research output: Contribution to journalArticle

Lin, W, Zhou, X, Burstein, D, Windhorst, R, Chen, J, Chen, WP, Jiang, Z, Kong, X, Ma, J, Sun, WH, Wu, H, Xue, S & Zhu, J 2003, 'Hα + [N II] observations of the H II regions in M81', Astronomical Journal, vol. 126, no. 3 1773, pp. 1286-1294. https://doi.org/10.1086/377519
Lin W, Zhou X, Burstein D, Windhorst R, Chen J, Chen WP et al. Hα + [N II] observations of the H II regions in M81. Astronomical Journal. 2003 Sep;126(3 1773):1286-1294. https://doi.org/10.1086/377519
Lin, Weipeng ; Zhou, Xu ; Burstein, David ; Windhorst, Rogier ; Chen, Jiansheng ; Chen, Wen Ping ; Jiang, Zhaoji ; Kong, Xu ; Ma, Jun ; Sun, Wei Hsin ; Wu, Hong ; Xue, Suijian ; Zhu, Jin. / Hα + [N II] observations of the H II regions in M81. In: Astronomical Journal. 2003 ; Vol. 126, No. 3 1773. pp. 1286-1294.
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abstract = "In a first of a series of studies of the Hα + [N II] emission from nearby spiral galaxies, we present measurements of Hα + [N II] emission from H II regions in M81. Our method uses large-field CCD images and long-slit spectra and is part of the ongoing Beijing-Arizona-Taipei-Connecticut Sky Survey (the BATC survey). The CCD images are taken with the National Astronomical Observatories of China (NAOC) 0.6/0.9 m f/3 Schmidt telescope at the Xinglong Observing Station, using a multicolor filter set. Spectra of 10 of the brightest H II regions are obtained using the NAOC 2.16 m telescope with a Tek 1024 × 1024 CCD. The continua of the spectra are calibrated by flux-calibrated images taken from the Schmidt observations. We determine the continuum component of our Hα + [N II] image via interpolation from the more accurately measured backgrounds (M81 starlight) obtained from the two neighboring (in wavelength) BATC filter images. We use the calibrated fluxes of Hα + [N II] emission from the spectra to normalize this interpolated, continuum-subtracted Hα + [N II] image. We estimate the zero-point uncertainty of the measured Hα + [N II] emission flux to be ∼8{\%}. A catalog of Hα + [N II] fluxes for 456 H II regions is provided, with those fluxes being on a more consistent linear scale than previously available. The logarithmically binned Hα + [N II] luminosity function of H II regions is found to have slope α = -0.70, consistent with previous results (which allowed α = -0.5 to -0.8). From the overall Hα + [N II] luminosity of the H II regions, the star formation rate of M81 is found to be ∼0.68 M⊙ yr-1, modulo uncertainty with extinction corrections.",
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AU - Burstein, David

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AU - Chen, Wen Ping

AU - Jiang, Zhaoji

AU - Kong, Xu

AU - Ma, Jun

AU - Sun, Wei Hsin

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AU - Xue, Suijian

AU - Zhu, Jin

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