Embedded Protostars in the Dust, Ice, and Gas In Time (DIGIT) Herschel Key Program: Continuum SEDs, and an Inventory of Characteristic Far-infrared Lines from PACS Spectroscopy
- Autor(en)
- , Joel D. Green, Neal J., II Evans, Jes K. Jørgensen, Gregory J. Herczeg, Lars E. Kristensen, Jeong-Eun Lee, Odyssefs Dionatos, Umut A. Yildiz, Colette Salyk, Gwendolyn Meeus, Jeroen Bouwman, Ruud Visser, Edwin A. Bergin, Ewine F. van Dishoeck, Michelle R. Rascati, Agata Karska, Tim A. van Kempen, Michael M. Dunham, Johan E. Lindberg, Davide Fedele
- Abstrakt
We present 50-210 μm spectral scans of 30 Class 0/I protostellar
sources, obtained with Herschel-PACS, and 0.5-1000 μm spectral energy
distributions, as part of the Dust, Ice, and Gas in Time Key Program.
Some sources exhibit up to 75 H2O lines ranging in excitation
energy from 100 to 2000 K, 12 transitions of OH, and CO rotational lines
ranging from J = 14 → 13 up to J = 40 → 39. [O I] is detected
in all but one source in the entire sample; among the sources with
detectable [O I] are two very low luminosity objects. The mean 63/145
μm [O I] flux ratio is 17.2 ± 9.2. The [O I] 63 μm line
correlates with L bol, but not with the time-averaged outflow
rate derived from low-J CO maps. [C II] emission is in general not local
to the source. The sample L bol increased by 1.25 (1.06) and
T bol decreased to 0.96 (0.96) of mean (median) values with
the inclusion of the Herschel data. Most CO rotational diagrams are
characterized by two optically thin components ({\langle { {N}}\rangle}
= (0.70 +/- 1.12){{} \times 10^{49}} total particles). { {N}}_CO
correlates strongly with L bol, but neither T rot
nor { {N}}_CO(warm)/{ {N}}_CO(hot) correlates with L bol,
suggesting that the total excited gas is related to the current source
luminosity, but that the excitation is primarily determined by the
physics of the interaction (e.g., UV-heating/shocks). Rotational
temperatures for H2O ({\langle {T_rot}\rangle } = 194 +/- 85
K) and OH ({\langle {T_rot}\rangle } =183 +/- 117 K) are generally lower
than for CO, and much of the scatter in the observations about the best
fit is attributed to differences in excitation conditions and optical
depths among the detected lines.
Herschel is an ESA space observatory with science instruments provided
by European-led Principal Investigator consortia and with important
participation from NASA.
- Organisation(en)
- Institut für Astrophysik
- Externe Organisation(en)
- Max-Planck-Institut für Astronomie, Peking University, Natural History Museum of Denmark, University of Copenhagen, University of Texas, Austin, Max-Planck-Institut für extraterrestrische Physik, Leiden University, Harvard-Smithsonian Center for Astrophysics, Kyung Hee University, National Optical Astronomy Observatory, Tucson, Universidad Autónoma de Madrid, University of Michigan, Joint ALMA Observatory, Yale University
- Journal
- The Astrophysical Journal: an international review of astronomy and astronomical physics
- Band
- 770
- Anzahl der Seiten
- 45
- ISSN
- 0004-637X
- DOI
- https://doi.org/10.1088/0004-637X/770/2/123
- Publikationsdatum
- 06-2013
- Peer-reviewed
- Ja
- ÖFOS 2012
- 103004 Astrophysik, 103003 Astronomie
- Schlagwörter
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/b0c43713-2ce7-40b4-9afe-2c94976b9736