TY - JOUR
T1 - Nothing to hide
T2 - An X-ray survey for young stellar objects in the Pipe Nebula
AU - Forbrich, Jan
AU - Posselt, Bettina
AU - Covey, Kevin R.
AU - Lada, Charles J.
PY - 2010/10/8
Y1 - 2010/10/8
N2 - We have previously analyzed sensitive mid-infrared observations to establish that the Pipe Nebula (PiN) has a very low star formation efficiency. That study focused on young stellar objects (YSOs) with excess infrared emission (i.e., protostars and pre-main-sequence stars with disks), however, and could have missed a population of more evolved pre-main-sequence stars or Class III objects (i.e., young stars with dissipated disks that no longer show excess infrared emission). Evolved pre-main-sequence stars are X-ray bright, so we have used ROSAT All-Sky Survey data to search for diskless pre-main-sequence stars throughout the PiN. We have also analyzed archival XMM-Newton observations of three prominent areas within the Pipe: Barnard 59 (B 59), containing a known cluster of YSOs; Barnard 68, a dense core that has yet to form stars; and the Pipe molecular ring, a high-extinction region in the bowl of the Pipe. We also characterize the X-ray properties of YSOs in B 59. The ROSAT and XMM-Newton data provide no indication of a significant population of more evolved pre-main-sequence stars within the Pipe, reinforcing our previous measurement of the Pipe's very low star formation efficiency.
AB - We have previously analyzed sensitive mid-infrared observations to establish that the Pipe Nebula (PiN) has a very low star formation efficiency. That study focused on young stellar objects (YSOs) with excess infrared emission (i.e., protostars and pre-main-sequence stars with disks), however, and could have missed a population of more evolved pre-main-sequence stars or Class III objects (i.e., young stars with dissipated disks that no longer show excess infrared emission). Evolved pre-main-sequence stars are X-ray bright, so we have used ROSAT All-Sky Survey data to search for diskless pre-main-sequence stars throughout the PiN. We have also analyzed archival XMM-Newton observations of three prominent areas within the Pipe: Barnard 59 (B 59), containing a known cluster of YSOs; Barnard 68, a dense core that has yet to form stars; and the Pipe molecular ring, a high-extinction region in the bowl of the Pipe. We also characterize the X-ray properties of YSOs in B 59. The ROSAT and XMM-Newton data provide no indication of a significant population of more evolved pre-main-sequence stars within the Pipe, reinforcing our previous measurement of the Pipe's very low star formation efficiency.
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U2 - 10.1088/0004-637X/719/1/691
DO - 10.1088/0004-637X/719/1/691
M3 - Article
AN - SCOPUS:78049294241
SN - 0004-637X
VL - 719
SP - 691
EP - 699
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
ER -