Discovery of X-rays from the protostellar outflow object HH2

  title={Discovery of X-rays from the protostellar outflow object HH2},
  author={Steven H. Pravdo and Eric D. Feigelson and Gordon P. Garmire and Yoshitomo Maeda and Yohko Tsuboi and J. M. Bally},
Herbig–Haro (HH) objects have been known for 50 years to be luminous condensations of gas in star-forming regions, but their underlying physical nature is still being elucidated. Previously suggested models encompass newborn stars, stellar winds clashing with nebular material, dense pockets of interstellar gas excited by shocks from outflows, and interstellar ‘bullets’ (ref. 6). Recent progress has been made with the jet-induced shock model, in which material streams out of young stellar… 

Shock-induced PDR in the Herbig-Haro object HH 2

We report mid-infrared ($5-17\mu m$) and SO, CO, $^{13}$CO millimeter line observations of the protostellar jet HH~2 and the parental molecular cloud. We have detected for the first time mid-infrared

The discovery of an expanding X-ray source in the HH 154 protostellar jet

Context. Protostellar jets are a new class of X-ray sources which has been discovered with both XMM-Newton and Chandra. The mechanism responsible for the X-ray emission is still not clear.

X-Rays from the Vicinity of the Protostar L1551 IRS 5: Reflection or Fast Shocks?

We present new Chandra X-Ray Observatory observations of the L1551 molecular cloud in Taurus. We find a compact, but slightly resolved, X-ray source, displaced westward from the IRS 5 binary


Protostellar jets appear at all stages of star formation when the accretion process is still at work. Jets travel at velocities of hundreds of km s−1, creating strong shocks when interacting with the

The X-ray puzzle of the L1551 IRS 5 jet

Protostars are actively accreting matter and they drive spectacular, dynamic outflows, which evolve on timescales of years. X-ray emission from these jets has been detected only in a few cases and

X-rays from protostellar jets: emission from continuous flows

Context. Recently X-ray emission from protostellar jets has been detected with both XMM- Newton and Chandra satellites, but the physical mechanism which can give rise to this emission is still

X-rays from HH210 in the Orion nebula

We report the detection during the Chandra Orion Ultradeep Project (COUP) of two soft, constant, and faint X-ray sources associated with the Herbig-Haro object HH210. HH210 is located at the tip of

The X-Ray Luminosities of Herbig-Haro Objects

The recent detection of X-ray emission from HH 2 and HH 154 with the Chandra and XMM-Newton satellites (respectively) have opened up an interesting, new observational possibility in the field of

A survey for ground-state OH masers towards a sample of Herbig–Haro objects

Herbig-Haro objects are regions of shocked gas and dust which are produced when collimated outflows from a protostar interact with the surrounding dense gas. They have many similarities to supernova

Recollimation boundary layers as X-ray sources in young stellar jets

Young stars accrete mass from circumstellar disks and, in many cases, the accretion coincides with a phase of massive outflows, which can be highly collimated. Those jets emit predominantly in the



A shocked cloudlet model for Herbig-Haro objects.

The results of moderately high dispersion spectra of Herbig-Haro objects Nos. 1 and 2 are reported. Relative emission line intensities, radial velocities, and emission line widths have been measured

An X-ray active region in Orion - X-rays from a Herbig-Haro object

The Imaging Proportional Counter on the Einstein X-ray Observatory has observed an approximately 1.0 deg square region in Orion centered near right ascension (1950) = 5 hours 34 min, declination = -6

A stellar-wind focusing mechanism as an explanation for Herbig-Haro objects

The steady state solution for the interaction of an isotropic stellar wind with a homogeneous, isothermal nebular environment is a spherical cavity, filled by unshocked stellar wind, and bounded by a

Radiative Bow Shock Models of Herbig-Haro Objects

The bow-shock models of HH objects presently constructed from a collection of 43 radiative-planar-shock models are used to predict the line ratios and line profiles expected from HH objects. It is

New VLA Observations of the HH 1-2 Region: Evidence for Density Enhancements Moving along the Axis of the VLA 1 Radio Jet

Using the Very Large Array, we have carried out new, sensitive radio continuum observations at 6 and 3.6 cm of the HH 1–2 region. The comparison between the 6 cm maps made from data taken in 1986.2

Herbig-Haro flows and the birth of low mass stars : proceedings of the 182nd Symposium of the International Astronomical Union, held in Chamonix, France, 20-26 January 1997

I. Herbig-Haro Objects, H2 Flows and Radio Jets. II. The Physics and Chemistry of Molecular Outflows. III. Theoretical Models. IV. Disks, Winds, and Magnetic Fields. V. Low- and High-Mass Protostars

The ultraviolet continuous and emission-line spectra of the Herbig-Haro objects HH 2 and HH 1

Recent studies of the continuous spectrum of Herbig-Haro (HH) objects at optical and near-infrared wavelengths and the observation of continuous radiation in the ultraviolet have shown an

X-ray CCD calibration for the AXAF CCD Imaging Spectrometer

Acquisition of ground calibration data from the AXAF CCD Imaging Spectrometer, one of two focal plane instruments on NASA's Advanced X-ray Astrophysics Facility, was completed in 1997. Here we

(Erratum) Letter to the Editor - The Tycho-2 catalogue of the 2.5 million brightest stars

Abstract : The Tycho-2 Catalogue presented here is an astrometric reference catalogue containing positions and proper motions as well as two-colour photometric data for the 2.5 million brightest

Radiative cooling of a low-density plasma

The radiative cooling coefficient has been calculated for a low-density, optically thin gas of cosmic abundances in the range 10/sup 4/-10/sup 8/ K incorporating significant elements through nickel