An X-ray superflare are from an infrared protostar

Grosso, N.; Montmerle, T.; Feigelson, E. D.; André, P.; Casanova, S.; Gregorio-Hetem, J.

doi:10.1038/387056a0

Cited by 129 publications

(136 citation statements)

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“…Y L W 15A (No. 54) ROSAT HRI detected an extraordinary X-ray Ñare from YLW 15A (Grosso et al 1997). The inferred luminosity, however, depends largely on the assumed spectrum.…”

Section: Comments On the Unidentiðed Sourcesmentioning

confidence: 99%

“…X-rays from class I sources (the late phase of protostars) have been reported in deep ASCA and ROSAT images of the o Ophiuchi cloud (Koyama et al 1994 ;Casanova et al 1995 ;Kamata et al 1997 ;Grosso et al 1997Carkner, Kozak, & Feigelson 1998 ;Tsuboi 1999 ;Tsuboi et al 2000 ;Grosso 2001). However, possible contamination from nearby TTSs (or others) would not be removed with the limited spatial resolution of ASCA.…”

Section: Introductionmentioning

confidence: 99%

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ChandraObservation of the ρ Ophiuchi Cloud

Imanishi

Koyama

Tsuboi

2001

ApJ

193

285

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We observed a 17@ ] 17@ region of the o Oph molecular cloud, using the ACIS-I array on board the Chandra X-Ray Observatory. A 100 ks exposure observation revealed D100 X-ray sources above the detection limit of D1028 ergs s~1. About two-thirds of the X-ray sources are identiÐed with an optical and/or IR counterpart, including signiÐcant numbers of class I, II, and III sources and a few brown dwarfs. The X-ray detection rate of class I sources is a surprisingly high 70%. Many X-ray Ñares, possibly because of the magnetic activity, are found from all of the classes. We make systematic spectral studies of the quiescent and Ñare X-rays for all the X-ray sources. The X-ray temperatures and absorptions of class I sources are generally larger than those of class II and III sources. In addition, X-ray Ñares from class I sources show slightly higher duty ratio, temperature, and luminosity than those of more evolved classes. We further give brief results on brown dwarfs, sources in a younger phase than class I, unclassiÐed, and unidentiÐed sources. Details for several selected young stellar objects, including the Ðrst detection of a neutral iron line (6.4 keV) from a class I source (YLW 16A), are separately addressed.

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“…Y L W 15A (No. 54) ROSAT HRI detected an extraordinary X-ray Ñare from YLW 15A (Grosso et al 1997). The inferred luminosity, however, depends largely on the assumed spectrum.…”

Section: Comments On the Unidentiðed Sourcesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

ChandraObservation of the ρ Ophiuchi Cloud

Imanishi

Koyama

Tsuboi

2001

ApJ

193

285

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“…In addition to these YSO generations, there is probably also a population of Class III sources, which is undistinguishable from the field star population in our study, but which should be looked for with proper search tools, such as e.g. X-ray mapping (Grosso et al 2000). Casali et al (1993) suggested that their submm sources without near-IR counterparts represented a second phase of active star formation in Serpens.…”

Section: Discussionmentioning

confidence: 99%

The young stellar population in the Serpens Cloud Core: An ISOCAM survey

Kaas

Olofsson

Bontemps

et al. 2004

A&A

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221

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Abstract. We present results from an ISOCAM survey in the two broad band filters LW2 (5−8.5 µm) and LW3 (12−18 µm) of a 0.13 square degree coverage of the Serpens Main Cloud Core. A total of 392 sources were detected in the 6.7 µm band and 139 in the 14.3 µm band to a limiting sensitivity of ∼2 mJy. We identified 53 Young Stellar Objects (YSOs) with mid-IR excess from the single colour index [14.3/6.7], and 8 additional YSOs from the H − K/K − m 6.7 diagram. Only 32 of these 61 sources were previously known to be YSO candidates. Only about 50% of the mid-IR excess sources show excesses in the near-IR J − H/H − K diagram. In the 48 square arcmin field covering the central Cloud Core the Class I/Class II number ratio is 19/18, i.e. about 10 times larger than in other young embedded clusters such as ρ Ophiuchi or Chamaeleon. The mid-IR fluxes of the Class I and flat-spectrum sources are found to be on the average larger than those of Class II sources. Stellar luminosities are estimated for the Class II sample, and its luminosity function is compatible with a coeval population of about 2 Myr which follows a three segment power-law IMF. For this age about 20% of the Class IIs are found to be young brown dwarf candidates. The YSOs are in general strongly clustered, the Class I sources more than the Class II sources, and there is an indication of sub-clustering. The sub-clustering of the protostar candidates has a spatial scale of 0.12 pc. These sub-clusters are found along the NW−SE oriented ridge and in very good agreement with the location of dense cores traced by millimeter data. The smallest clustering scale for the Class II sources is about 0.25 pc, similar to what was found for ρ Ophiuchi. Our data show evidence that star formation in Serpens has proceeded in several phases, and that a "microburst" of star formation has taken place very recently, probably within the last 10 5 yrs.Key words. stars: formation -stars: pre-main-sequence -stars: luminosity function, mass functionstars: low-mass, brown dwarfs -ISM: individual objects: Serpens Cloud Core Send offprint requests to: A. A. Kaas, e-mail: akaas@not.iac.es Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands and the United Kingdom) and with participation of ISAS and NASA. Tables 2 and 3 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via

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“…The large-scale structure of the ρ Ophiuchi molecular cloud has been revealed by extensive molecular 13 CO line mapping (Loren 1989a,b). Surveys for young stars in Ophiuchus include Casanova et al (1995), Kamata et al (1997), Grosso et al (2000), Imanishi et al (2002), Ozawa et al (2005), and Pillitteri et al (2010) in X-rays; Wilking et al (1987Wilking et al ( , 2005 in the visual; Greene & Young (1992a), Allen et al (2002), and Alves de Oliveira & Casali (2008) in the near-infrared; Young et al (1986a), Wilking et al (2001), Padgett et al (2008), Evans et al (2009), andMcClure et al (2010) in the mid-and far-infrared; and Motte et al (1998), Johnstone et al (2000), Stanke et al (2006), Andrews & Williams (2007), and Andrews et al (2010) at submillimeter and millimeter wavelengths. By combining the results of the previous studies, Wilking et al (2008) compiled a list of 316 young stars in L1688, the densest core of Ophiuchus.…”

Section: Introductionmentioning

confidence: 99%

Proper motions of molecular hydrogen outflows in theρOphiuchi molecular cloud

Zhang

Brandner

Wang

et al. 2013

A&A

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Context. Proper motion measurements provide unique and powerful means to identify the driving sources of mass outflows, which are of particular importance in regions with complex star formation activity and deeply embedded protostars. They also provide the necessary kinematic information to study the dynamics of mass outflows, the interaction between outflows and the ambient medium, and the evolution of outflows with the age of the driving sources. Aims. We aim to take a census of molecular hydrogen emission line objects (MHOs) in the ρ Ophiuchi molecular cloud and to make the first systematic proper motion measurements of these objects in this region. The driving sources are identified based on the measured proper motions, and the outflow properties are characterized. The relationship between outflow properties and the evolutionary stages of the driving sources are also investigated. Methods. Deep H 2 near-infrared imaging is performed to search for molecular hydrogen emission line objects. Multi-epoch data are used to derive the proper motions of the features of these objects, and the lengths and opening angles of the molecular hydrogen outflows. Results. Our imaging covers an area of ∼0.11 deg 2 toward the L1688 core in the ρ Ophiuchi molecular cloud. In total, six new MHOs are discovered, 32 previously known MHOs are detected, and the proper motions for 86 features of the MHOs are measured. The proper motions lie in the range of 14 to 247 mas/yr, corresponding to transversal velocities of 8 to 140 km s −1 with a median velocity of about 35 km s −1 . Based on morphology and proper motion measurements, 27 MHOs are ascribed to 21 driving sources. The molecular hydrogen outflows have a median length of ∼0.04 pc and random orientations. We find no obvious correlation between H 2 jet length, jet opening angle, and the evolutionary stage of the driving sources as defined by their spectral indices. We find that the fraction of protostars (23%) that drive molecular hydrogen outflows is similar to the one for Class II sources (15%). For most molecular hydrogen outflows, no obvious velocity variation along the outflow has been found. Conclusions. In Ophiuchus the frequency of occurrence of molecular hydrogen outflows has no strong dependency on the evolutionary stage of the driving source during the evolution from the protostellar stage to the classical T Tauri stage.

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An X-ray superflare are from an infrared protostar

Cited by 129 publications

References 19 publications

ChandraObservation of the ρ Ophiuchi Cloud

ChandraObservation of the ρ Ophiuchi Cloud

The young stellar population in the Serpens Cloud Core: An ISOCAM survey

Proper motions of molecular hydrogen outflows in theρOphiuchi molecular cloud

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