Simultaneous X-ray, radio, near-infrared, and optical monitoring of young stellar objects in the Coronet cluster

J. Forbrich, Th Preibisch, K. M. Menten, R. Neuhäuser, F. M. Walter, M. Tamura, N. Matsunaga, N. Kusakabe, Y. Nakajima, A. Brandeker, S. Fornasier, Bettina Posselt, K. Tachihara, C. Broeg

Research output: Contribution to journalArticle

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Abstract

Context. Multi-wavelength (X-ray to radio) monitoring of Young Stellar Objects (YSOs) can provide important information about physical processes at the stellar surface, in the stellar corona, and/or in the inner circumstellar disk regions. While coronal processes should mainly cause variations in the X-ray and radio bands, accretion processes may be traced by time-correlated variability in the X-ray and optical/infrared bands. Several multi-wavelength studies have been successfully performed for field stars and ∼1-10 Myr old T Tauri stars, but so far no such study succeeded in detecting simultaneous X-ray to radio variability in extremely young objects like class I and class 0 protostars. Aims. Here we present the first simultaneous X-ray, radio, near-infrared, and optical monitoring of YSOs, targeting the Coronet cluster in the Corona Australis star-forming region, which harbors at least one class 0 protostar, several class I objects, numerous T Tauri stars, and a few Herbig AeBe stars. Methods. In August 2005, we obtained five epochs of Chandra X-ray observations on nearly successive days accompanied by simultaneous radio observations at the NRAO Very Large Array during four epochs, as well as by simultaneous optical and near-infrared observations from ground-based telescopes in Chile and South Africa. Results. Seven objects are detected simultaneously in the X-ray, radio, and optical/infrared bands; they constitute our core sample. While most of these sources exhibit clear variability in the X-ray regime and several also display optical/infrared variability, none of them shows significant radio variability on the timescales probed. We also do not find any case of clearly time-correlated optical/infrared and X-ray variability. Remarkable intra-band variability is found for the class I protostar IRS 5 which shows much lower radio fluxes than in previous observations, and the Herbig Ae star R CrA, which displays enhanced X-ray emission during the last two epochs, but no time-correlated variations are seen for these objects in the other bands. The two components of S CrA vary nearly synchronously in the I band. Conclusions. The absence of time-correlated multi-wavelength variability suggests that there is no direct link between the X-ray and optical/infrared emission and supports the notion that accretion is not an important source for the X-ray emission of these YSOs. No significant radio variability was found on timescales of days.

Original languageEnglish (US)
Pages (from-to)1003-1013
Number of pages11
JournalAstronomy and Astrophysics
Volume464
Issue number3
DOIs
StatePublished - Mar 1 2007

Fingerprint

near infrared
radio
monitoring
x rays
protostars
T Tauri stars
time measurement
wavelength
stars
corona
young
stellar coronas
accretion
wavelengths
timescale
Indian spacecraft
star distribution
Very Large Array (VLA)
Republic of South Africa
radio observation

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Forbrich, J., Preibisch, T., Menten, K. M., Neuhäuser, R., Walter, F. M., Tamura, M., ... Broeg, C. (2007). Simultaneous X-ray, radio, near-infrared, and optical monitoring of young stellar objects in the Coronet cluster. Astronomy and Astrophysics, 464(3), 1003-1013. https://doi.org/10.1051/0004-6361:20066158
Forbrich, J. ; Preibisch, Th ; Menten, K. M. ; Neuhäuser, R. ; Walter, F. M. ; Tamura, M. ; Matsunaga, N. ; Kusakabe, N. ; Nakajima, Y. ; Brandeker, A. ; Fornasier, S. ; Posselt, Bettina ; Tachihara, K. ; Broeg, C. / Simultaneous X-ray, radio, near-infrared, and optical monitoring of young stellar objects in the Coronet cluster. In: Astronomy and Astrophysics. 2007 ; Vol. 464, No. 3. pp. 1003-1013.
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abstract = "Context. Multi-wavelength (X-ray to radio) monitoring of Young Stellar Objects (YSOs) can provide important information about physical processes at the stellar surface, in the stellar corona, and/or in the inner circumstellar disk regions. While coronal processes should mainly cause variations in the X-ray and radio bands, accretion processes may be traced by time-correlated variability in the X-ray and optical/infrared bands. Several multi-wavelength studies have been successfully performed for field stars and ∼1-10 Myr old T Tauri stars, but so far no such study succeeded in detecting simultaneous X-ray to radio variability in extremely young objects like class I and class 0 protostars. Aims. Here we present the first simultaneous X-ray, radio, near-infrared, and optical monitoring of YSOs, targeting the Coronet cluster in the Corona Australis star-forming region, which harbors at least one class 0 protostar, several class I objects, numerous T Tauri stars, and a few Herbig AeBe stars. Methods. In August 2005, we obtained five epochs of Chandra X-ray observations on nearly successive days accompanied by simultaneous radio observations at the NRAO Very Large Array during four epochs, as well as by simultaneous optical and near-infrared observations from ground-based telescopes in Chile and South Africa. Results. Seven objects are detected simultaneously in the X-ray, radio, and optical/infrared bands; they constitute our core sample. While most of these sources exhibit clear variability in the X-ray regime and several also display optical/infrared variability, none of them shows significant radio variability on the timescales probed. We also do not find any case of clearly time-correlated optical/infrared and X-ray variability. Remarkable intra-band variability is found for the class I protostar IRS 5 which shows much lower radio fluxes than in previous observations, and the Herbig Ae star R CrA, which displays enhanced X-ray emission during the last two epochs, but no time-correlated variations are seen for these objects in the other bands. The two components of S CrA vary nearly synchronously in the I band. Conclusions. The absence of time-correlated multi-wavelength variability suggests that there is no direct link between the X-ray and optical/infrared emission and supports the notion that accretion is not an important source for the X-ray emission of these YSOs. No significant radio variability was found on timescales of days.",
author = "J. Forbrich and Th Preibisch and Menten, {K. M.} and R. Neuh{\"a}user and Walter, {F. M.} and M. Tamura and N. Matsunaga and N. Kusakabe and Y. Nakajima and A. Brandeker and S. Fornasier and Bettina Posselt and K. Tachihara and C. Broeg",
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Forbrich, J, Preibisch, T, Menten, KM, Neuhäuser, R, Walter, FM, Tamura, M, Matsunaga, N, Kusakabe, N, Nakajima, Y, Brandeker, A, Fornasier, S, Posselt, B, Tachihara, K & Broeg, C 2007, 'Simultaneous X-ray, radio, near-infrared, and optical monitoring of young stellar objects in the Coronet cluster', Astronomy and Astrophysics, vol. 464, no. 3, pp. 1003-1013. https://doi.org/10.1051/0004-6361:20066158

Simultaneous X-ray, radio, near-infrared, and optical monitoring of young stellar objects in the Coronet cluster. / Forbrich, J.; Preibisch, Th; Menten, K. M.; Neuhäuser, R.; Walter, F. M.; Tamura, M.; Matsunaga, N.; Kusakabe, N.; Nakajima, Y.; Brandeker, A.; Fornasier, S.; Posselt, Bettina; Tachihara, K.; Broeg, C.

In: Astronomy and Astrophysics, Vol. 464, No. 3, 01.03.2007, p. 1003-1013.

Research output: Contribution to journalArticle

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T1 - Simultaneous X-ray, radio, near-infrared, and optical monitoring of young stellar objects in the Coronet cluster

AU - Forbrich, J.

AU - Preibisch, Th

AU - Menten, K. M.

AU - Neuhäuser, R.

AU - Walter, F. M.

AU - Tamura, M.

AU - Matsunaga, N.

AU - Kusakabe, N.

AU - Nakajima, Y.

AU - Brandeker, A.

AU - Fornasier, S.

AU - Posselt, Bettina

AU - Tachihara, K.

AU - Broeg, C.

PY - 2007/3/1

Y1 - 2007/3/1

N2 - Context. Multi-wavelength (X-ray to radio) monitoring of Young Stellar Objects (YSOs) can provide important information about physical processes at the stellar surface, in the stellar corona, and/or in the inner circumstellar disk regions. While coronal processes should mainly cause variations in the X-ray and radio bands, accretion processes may be traced by time-correlated variability in the X-ray and optical/infrared bands. Several multi-wavelength studies have been successfully performed for field stars and ∼1-10 Myr old T Tauri stars, but so far no such study succeeded in detecting simultaneous X-ray to radio variability in extremely young objects like class I and class 0 protostars. Aims. Here we present the first simultaneous X-ray, radio, near-infrared, and optical monitoring of YSOs, targeting the Coronet cluster in the Corona Australis star-forming region, which harbors at least one class 0 protostar, several class I objects, numerous T Tauri stars, and a few Herbig AeBe stars. Methods. In August 2005, we obtained five epochs of Chandra X-ray observations on nearly successive days accompanied by simultaneous radio observations at the NRAO Very Large Array during four epochs, as well as by simultaneous optical and near-infrared observations from ground-based telescopes in Chile and South Africa. Results. Seven objects are detected simultaneously in the X-ray, radio, and optical/infrared bands; they constitute our core sample. While most of these sources exhibit clear variability in the X-ray regime and several also display optical/infrared variability, none of them shows significant radio variability on the timescales probed. We also do not find any case of clearly time-correlated optical/infrared and X-ray variability. Remarkable intra-band variability is found for the class I protostar IRS 5 which shows much lower radio fluxes than in previous observations, and the Herbig Ae star R CrA, which displays enhanced X-ray emission during the last two epochs, but no time-correlated variations are seen for these objects in the other bands. The two components of S CrA vary nearly synchronously in the I band. Conclusions. The absence of time-correlated multi-wavelength variability suggests that there is no direct link between the X-ray and optical/infrared emission and supports the notion that accretion is not an important source for the X-ray emission of these YSOs. No significant radio variability was found on timescales of days.

AB - Context. Multi-wavelength (X-ray to radio) monitoring of Young Stellar Objects (YSOs) can provide important information about physical processes at the stellar surface, in the stellar corona, and/or in the inner circumstellar disk regions. While coronal processes should mainly cause variations in the X-ray and radio bands, accretion processes may be traced by time-correlated variability in the X-ray and optical/infrared bands. Several multi-wavelength studies have been successfully performed for field stars and ∼1-10 Myr old T Tauri stars, but so far no such study succeeded in detecting simultaneous X-ray to radio variability in extremely young objects like class I and class 0 protostars. Aims. Here we present the first simultaneous X-ray, radio, near-infrared, and optical monitoring of YSOs, targeting the Coronet cluster in the Corona Australis star-forming region, which harbors at least one class 0 protostar, several class I objects, numerous T Tauri stars, and a few Herbig AeBe stars. Methods. In August 2005, we obtained five epochs of Chandra X-ray observations on nearly successive days accompanied by simultaneous radio observations at the NRAO Very Large Array during four epochs, as well as by simultaneous optical and near-infrared observations from ground-based telescopes in Chile and South Africa. Results. Seven objects are detected simultaneously in the X-ray, radio, and optical/infrared bands; they constitute our core sample. While most of these sources exhibit clear variability in the X-ray regime and several also display optical/infrared variability, none of them shows significant radio variability on the timescales probed. We also do not find any case of clearly time-correlated optical/infrared and X-ray variability. Remarkable intra-band variability is found for the class I protostar IRS 5 which shows much lower radio fluxes than in previous observations, and the Herbig Ae star R CrA, which displays enhanced X-ray emission during the last two epochs, but no time-correlated variations are seen for these objects in the other bands. The two components of S CrA vary nearly synchronously in the I band. Conclusions. The absence of time-correlated multi-wavelength variability suggests that there is no direct link between the X-ray and optical/infrared emission and supports the notion that accretion is not an important source for the X-ray emission of these YSOs. No significant radio variability was found on timescales of days.

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