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Title: COMPLEX STRUCTURE IN CLASS 0 PROTOSTELLAR ENVELOPES. II. KINEMATIC STRUCTURE FROM SINGLE-DISH AND INTERFEROMETRIC MOLECULAR LINE MAPPING

Abstract

We present a study of dense molecular gas kinematics in 17 nearby protostellar systems using single-dish and interferometric molecular line observations. The non-axisymmetric envelopes around a sample of Class 0/I protostars were mapped in the N{sub 2}H{sup +} (J = 1 {yields} 0) tracer with the IRAM 30 m, CARMA, and Plateau de Bure Interferometer, as well as NH{sub 3} (1,1) with the Very Large Array. The molecular line emission is used to construct line-center velocity and linewidth maps for all sources to examine the kinematic structure in the envelopes on spatial scales from 0.1 pc to {approx}1000 AU. The direction of the large-scale velocity gradients from single-dish mapping is within 45{sup 0} of normal to the outflow axis in more than half the sample. Furthermore, the velocity gradients are often quite substantial, the average being {approx}2.3 km s{sup -1} pc{sup -1}. The interferometric data often reveal small-scale velocity structure, departing from the more gradual large-scale velocity gradients. In some cases, this likely indicates accelerating infall and/or rotational spin-up in the inner envelope; the median velocity gradient from the interferometric data is {approx}10.7 km s{sup -1} pc{sup -1}. In two systems, we detect high-velocity HCO{sup +} (J = 1 {yields}more » 0) emission inside the highest-velocity N{sub 2}H{sup +} emission. This enables us to study the infall and rotation close to the disk and estimate the central object masses. The velocity fields observed on large and small scales are more complex than would be expected from rotation alone, suggesting that complex envelope structure enables other dynamical processes (i.e., infall) to affect the velocity field.« less

Authors:
; ;  [1]; ;  [2];  [3];  [4];  [5];  [6]
  1. Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)
  2. Department of Astronomy, University of Illinois, Urbana, IL 61801 (United States)
  3. National Radio Astronomy Observatory, Socorro, NM 87801 (United States)
  4. Departament d'Astronomia i Meteorologia, Universitat de Barcelona, 08028 Barcelona, Catalunya (Spain)
  5. UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble F-38041 (France)
  6. Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599 (United States)
Publication Date:
OSTI Identifier:
21587407
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 740; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/740/1/45; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; INTERFEROMETRY; MAPPING; PROTOSTARS; VELOCITY

Citation Formats

Tobin, John J, Hartmann, Lee, Bergin, Edwin A, Chiang, Hsin-Fang, Looney, Leslie W, Chandler, Claire J, Masque, Josep M, Maret, Sebastien, and Heitsch, Fabian. COMPLEX STRUCTURE IN CLASS 0 PROTOSTELLAR ENVELOPES. II. KINEMATIC STRUCTURE FROM SINGLE-DISH AND INTERFEROMETRIC MOLECULAR LINE MAPPING. United States: N. p., 2011. Web. doi:10.1088/0004-637X/740/1/45; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Tobin, John J, Hartmann, Lee, Bergin, Edwin A, Chiang, Hsin-Fang, Looney, Leslie W, Chandler, Claire J, Masque, Josep M, Maret, Sebastien, & Heitsch, Fabian. COMPLEX STRUCTURE IN CLASS 0 PROTOSTELLAR ENVELOPES. II. KINEMATIC STRUCTURE FROM SINGLE-DISH AND INTERFEROMETRIC MOLECULAR LINE MAPPING. United States. https://doi.org/10.1088/0004-637X/740/1/45; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Tobin, John J, Hartmann, Lee, Bergin, Edwin A, Chiang, Hsin-Fang, Looney, Leslie W, Chandler, Claire J, Masque, Josep M, Maret, Sebastien, and Heitsch, Fabian. 2011. "COMPLEX STRUCTURE IN CLASS 0 PROTOSTELLAR ENVELOPES. II. KINEMATIC STRUCTURE FROM SINGLE-DISH AND INTERFEROMETRIC MOLECULAR LINE MAPPING". United States. https://doi.org/10.1088/0004-637X/740/1/45; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21587407,
title = {COMPLEX STRUCTURE IN CLASS 0 PROTOSTELLAR ENVELOPES. II. KINEMATIC STRUCTURE FROM SINGLE-DISH AND INTERFEROMETRIC MOLECULAR LINE MAPPING},
author = {Tobin, John J and Hartmann, Lee and Bergin, Edwin A and Chiang, Hsin-Fang and Looney, Leslie W and Chandler, Claire J and Masque, Josep M and Maret, Sebastien and Heitsch, Fabian},
abstractNote = {We present a study of dense molecular gas kinematics in 17 nearby protostellar systems using single-dish and interferometric molecular line observations. The non-axisymmetric envelopes around a sample of Class 0/I protostars were mapped in the N{sub 2}H{sup +} (J = 1 {yields} 0) tracer with the IRAM 30 m, CARMA, and Plateau de Bure Interferometer, as well as NH{sub 3} (1,1) with the Very Large Array. The molecular line emission is used to construct line-center velocity and linewidth maps for all sources to examine the kinematic structure in the envelopes on spatial scales from 0.1 pc to {approx}1000 AU. The direction of the large-scale velocity gradients from single-dish mapping is within 45{sup 0} of normal to the outflow axis in more than half the sample. Furthermore, the velocity gradients are often quite substantial, the average being {approx}2.3 km s{sup -1} pc{sup -1}. The interferometric data often reveal small-scale velocity structure, departing from the more gradual large-scale velocity gradients. In some cases, this likely indicates accelerating infall and/or rotational spin-up in the inner envelope; the median velocity gradient from the interferometric data is {approx}10.7 km s{sup -1} pc{sup -1}. In two systems, we detect high-velocity HCO{sup +} (J = 1 {yields} 0) emission inside the highest-velocity N{sub 2}H{sup +} emission. This enables us to study the infall and rotation close to the disk and estimate the central object masses. The velocity fields observed on large and small scales are more complex than would be expected from rotation alone, suggesting that complex envelope structure enables other dynamical processes (i.e., infall) to affect the velocity field.},
doi = {10.1088/0004-637X/740/1/45; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
url = {https://www.osti.gov/biblio/21587407}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 740,
place = {United States},
year = {Mon Oct 10 00:00:00 EDT 2011},
month = {Mon Oct 10 00:00:00 EDT 2011}
}