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Title: SIMULTANEOUS X-RAY AND RADIO OBSERVATIONS OF YOUNG STELLAR OBJECTS IN NGC 1333 AND IC 348

Abstract

Young stellar objects (YSOs) and in particular protostars are known to show a variety of high-energy processes. Observations in the X-ray and centimetric radio wavelength ranges are thought to constrain some of these processes, e.g., coronal-type magnetic activity. There is a well-known empirical correlation of radio and X-ray luminosities in active stars, the so-called Guedel-Benz (GB) relation. Previous evidence of whether YSOs are compatible with this relation remains inconclusive for the earliest evolutionary stages. The main difficulty is that due to the extreme variability of these sources, simultaneous observations are essential. Until now, only a few YSOs and only a handful of protostars have been observed simultaneously in the X-ray and radio range. To expand the sample, we have obtained such observations of two young clusters rich in protostars, NGC 1333 and IC 348. While the absolute sensitivity is lower for these regions than for more nearby clusters like CrA, we find that even in deep continuum observations carried out with the NRAO Very Large Array (VLA), the radio detection fraction for protostars in these clusters is much lower than the X-ray detection fraction. Very few YSOs are detected in both bands, and we find the radio and X-ray populationsmore » among YSOs to be largely distinct. We combine these new results with previous simultaneous Chandra and VLA observations of star-forming regions and find that YSOs with detections in both bands appear to be offset toward higher radio luminosities for given X-ray luminosities when compared with the GB relation, although even in this sensitive data set most sources are too weak for the radio detections to provide information on the emission processes. The considerably improved sensitivity of the Expanded VLA will provide a better census of the YSO radio population as well as better constraints on the emission mechanisms.« less

Authors:
;  [1];  [2]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  2. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
Publication Date:
OSTI Identifier:
21578343
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 736; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/736/1/25; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EMISSION; LUMINOSITY; PROTOSTARS; RADIOWAVE RADIATION; X RADIATION; ELECTROMAGNETIC RADIATION; IONIZING RADIATIONS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; RADIATIONS

Citation Formats

Forbrich, Jan, Wolk, Scott J., and Osten, Rachel A. SIMULTANEOUS X-RAY AND RADIO OBSERVATIONS OF YOUNG STELLAR OBJECTS IN NGC 1333 AND IC 348. United States: N. p., 2011. Web. doi:10.1088/0004-637X/736/1/25.
Forbrich, Jan, Wolk, Scott J., & Osten, Rachel A. SIMULTANEOUS X-RAY AND RADIO OBSERVATIONS OF YOUNG STELLAR OBJECTS IN NGC 1333 AND IC 348. United States. doi:10.1088/0004-637X/736/1/25.
Forbrich, Jan, Wolk, Scott J., and Osten, Rachel A. Wed . "SIMULTANEOUS X-RAY AND RADIO OBSERVATIONS OF YOUNG STELLAR OBJECTS IN NGC 1333 AND IC 348". United States. doi:10.1088/0004-637X/736/1/25.
@article{osti_21578343,
title = {SIMULTANEOUS X-RAY AND RADIO OBSERVATIONS OF YOUNG STELLAR OBJECTS IN NGC 1333 AND IC 348},
author = {Forbrich, Jan and Wolk, Scott J. and Osten, Rachel A.},
abstractNote = {Young stellar objects (YSOs) and in particular protostars are known to show a variety of high-energy processes. Observations in the X-ray and centimetric radio wavelength ranges are thought to constrain some of these processes, e.g., coronal-type magnetic activity. There is a well-known empirical correlation of radio and X-ray luminosities in active stars, the so-called Guedel-Benz (GB) relation. Previous evidence of whether YSOs are compatible with this relation remains inconclusive for the earliest evolutionary stages. The main difficulty is that due to the extreme variability of these sources, simultaneous observations are essential. Until now, only a few YSOs and only a handful of protostars have been observed simultaneously in the X-ray and radio range. To expand the sample, we have obtained such observations of two young clusters rich in protostars, NGC 1333 and IC 348. While the absolute sensitivity is lower for these regions than for more nearby clusters like CrA, we find that even in deep continuum observations carried out with the NRAO Very Large Array (VLA), the radio detection fraction for protostars in these clusters is much lower than the X-ray detection fraction. Very few YSOs are detected in both bands, and we find the radio and X-ray populations among YSOs to be largely distinct. We combine these new results with previous simultaneous Chandra and VLA observations of star-forming regions and find that YSOs with detections in both bands appear to be offset toward higher radio luminosities for given X-ray luminosities when compared with the GB relation, although even in this sensitive data set most sources are too weak for the radio detections to provide information on the emission processes. The considerably improved sensitivity of the Expanded VLA will provide a better census of the YSO radio population as well as better constraints on the emission mechanisms.},
doi = {10.1088/0004-637X/736/1/25},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 736,
place = {United States},
year = {2011},
month = {7}
}