Nothing to hide: An X-ray survey for young stellar objects in the Pipe Nebula

Abstract

We have previously analyzed sensitive mid-infrared observations to establish that the Pipe Nebula has a very low star-formation efficiency. That study focused on 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 Pipe Nebula. We have also analyzed archival XMM-Newton observations of three prominent areas within the Pipe: Barnard 59, containing a known cluster of young stellar objects; 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 additionally characterize the X-ray properties of YSOs in Barnard 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.

Accepted for publication in ApJ

References in corpus (7)

• The Second-Generation Guide Star Catalog: Description and Properties
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• 2MASS wide field extinction maps - I. The Pipe nebula
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• The Gould's Belt Very Large Array Survey I: The Ophiuchus complex
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• The molecular gas content of the Pipe Nebula I. Direct evidence of outflow-generated turbulence in B59?
• Hot methanol in the [BHB2007] 11 protobinary system: hot corino versus shock origin? : FAUST V
• Some like it cold: molecular emission and effective dust temperatures of dense cores in the Pipe Nebula
• The Gould's Belt Very Large Array Survey V: The Perseus Region
• Smoke in the Pipe Nebula: dust emission and grain growth in the starless core FeSt 1-457
• Distortion of Magnetic Fields in a Starless Core IV: Magnetic Field Scaling on Density and Mass-to-flux Ratio Distribution in FeSt 1-457
• Not so different after all: Properties and Spatial Structure of Column Density Peaks in the Pipe and Orion A Clouds
• Testing the star formation scaling relations in the clumps of the North American and Pelican cloud complexes
• Distortion of Magnetic Fields in a Starless Core VI: Application of Flux Freezing Model and Core Formation of FeSt 1-457
• Star formation history of Canis Major OB1 - II. A bimodal X-ray population revealed by XMM-Newton
• The role of theta Oph in the formation and evolution of the Pipe Nebula - is star formation ever isolated?
• Distortion of Magnetic Fields in the Dense Core CB81 (L1774, Pipe 42) in the Pipe Nebula
• Star Formation in the Local Milky Way
• Unveiling the role of magnetic fields in an accreting filament onto a young protocluster
• FORCAST imaging of two small nearby Clusters: The Coronet and B59