Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2009-06-03
Astrophys.J.699:L165-L168,2009
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
Accepted for publication in ApJ Letters (editorial corrections included)
Scientific paper
10.1088/0004-637X/699/2/L165
We present the first detection of neutral atomic oxygen (3P_1-3P_2 fine structure line at ~63um) toward the Horsehead photodissociation region (PDR). The cloud has been mapped with the Spitzer Space Telescope at far-IR (FIR) wavelengths using MIPS in the spectral energy distribution (SED) mode. The [OI]63um line peaks at the illuminated edge of the cloud at AV~0.1-0.5 (inward the gas becomes too cold and outward the gas density drops). The luminosity carried by the [OI]63um line represents a significant fraction of the total FIR dust luminosity (I_63/I_FIR~4x10^-3). We analyze the dust continuum emission and the nonlocal OI excitation and radiative transfer in detail. The observations are reproduced with a gas density of n_H~10^4 cm^-3 and gas and dust temperatures of T_k~100 K and T_d~30 K. We conclude that the determination of the OI 3P_J level populations and emergent line intensities at such ``low'' densities is a complex non-LTE problem. FIR radiative pumping, [OI]63um subthermal emission, [OI]145um suprathermal and even maser emission can occur and decrease the resulting [OI]63/145 intensity ratio. The Herschel Space Observatory, observing from ~55 to 672um, will allow us to exploit the diagnostic power of FIR fine structure lines with unprecedented resolution and sensitivity.
Compiegne Mathieu
Goicoechea Javier R.
Habart Emilie
No associations
LandOfFree
Far-Infrared detection of neutral atomic oxygen toward the Horsehead Nebula does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Far-Infrared detection of neutral atomic oxygen toward the Horsehead Nebula, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Far-Infrared detection of neutral atomic oxygen toward the Horsehead Nebula will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-193943