High-Mass, OB Star Formation in M51: [ITAL]HUBBLE SPACE TELESCOPE[/ITAL][ITAL]Hubble Space Telescope[/ITAL] Hα and P[CLC]a[/CLC]α Imaging | doi.page

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High-Mass, OB Star Formation in M51: [ITAL]HUBBLE SPACE TELESCOPE[/ITAL][ITAL]Hubble Space Telescope[/ITAL] Hα and P[CLC]a[/CLC]α Imaging

The Astronomical Journal2001Vol. 122(6), pp. 3017–3045

Citations Over TimeTop 10% of 2001 papers

N. Z. Scoville, M. Polletta, S. P. Ewald, S. Stolovy, Rodger I. Thompson, Marcia Rieke

Abstract

We have obtained Hα and Paα emission-line images covering the central 3'–4' of M51 using the WFPC2 and NICMOS instruments on the Hubble Space Telescope to study the high-mass stellar population. The 01–02 pixels provide 4.6–9 pc resolution in M51, and the Hα/Paα line ratios are used to obtain extinction estimates. A sample of 1373 Hα emission regions is cataloged using an automated and uniform measurement algorithm. Their sizes are typically 10–100 pc. The luminosity function for the Hα emission regions is obtained over the range LHα = 1036 to 2 × 1039 ergs s-1. The luminosity function is fitted well by a power law with dN/d ln L ∝ L-1.01. The power law is significantly truncated, and no regions were found with observed LHα above 2 × 1039 ergs s-1 (uncorrected for extinction). (The maximum seen in ground-based studies is approximately a factor of 5 higher, very likely because of the blending of multiple regions.) The extinctions derived here increase the maximum intrinsic luminosity to above 1040 ergs s-1. The logarithmically binned luminosity function is also somewhat steeper (α = -1.01) than that found from ground-based imaging (α = -0.5 to -0.8)—probably also a result of our resolving regions that were blended in the ground-based images. The two-point correlation function for the H II regions exhibits strong clustering on scales ≤2'', or 96 pc.

Citations Over TimeTop 10% of 2001 papers

Abstract

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