English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

X-rays from very young stars are powerful probes to investigate themechanisms at work in the very first stages of the star formation and theorigin of X-ray emission in very young stars. We present results from a 500 kslong observation of the Rho Ophiuchi cloud with a XMM-Newton large programnamed DROXO, aiming at studying the X-ray emission of deeply embedded YoungStellar Objects (YSOs). The data acquired during the DROXO program were reducedwith SAS software, and filtered in time and energy to improve the signal tonoise of detected sources; light curves and spectra were obtained. We detected111 sources, 61 of them associated with rho Ophiuchi YSOs as identified frominfrared observations with ISOCAM. Specifically, we detected 9 out of 11 ClassI, 31 out of 48 Class II and 15 out 16 Class III objects. Six objects out of 21classified Class III candidates are also detected. At the same time we suggestthat 15 Class III candidates that remain undetected at log Lx < 28.3 are notrelated to the cloud population. The global detection rate is ~64%. We haveachieved a flux sensitivity of ~5 x 10^{-15} erg s^{-1} cm^{-2}. The Lx toL_bol ratio shows saturation at a value of ~ -3.5 for stars with T_eff <= 5000K or 0.7 M_sun as observed in the Orion Nebula. The plasma temperatures and thespectrum absorption show a decline with YSO class, with Class I YSOs beinghotter and more absorbed than Class II and III YSOs. In one star (GY 266) withinfrared counterpart in 2MASS and Spitzer catalogs we have detected a softexcess in the X-ray spectrum which is best fitted by a cold thermal componentless absorbed than the main thermal component of the plasma. Such a softcomponent hints to the presence of plasma heated by shocks due to jets outsidethe dense circumstellar material.

Results from DROXO. III. Observation, source list and X-ray properties of sources detected in the "Deep Rho Ophiuchi XMM-Newton Observation"