A dataset provided by the European Space Agency

Name OT2_tharriso_6
Title Unraveling the Outburst and Quiescent Emission Properties of the Enigmatic Binary Cir X-1


DOI https://doi.org/10.5270/esa-30zenhb
Author European Space Agency
Description Cir X-1 is an unusual X-ray binary in that it has large scale outbursts every 16.58 d.
The cause of these outbursts is believed to be due to episodic mass transfer
events that occur when a non-degenerate companion, in a highly eccentric orbit
around a compact object, passes through periastron. In the 1970.s, Cir X-1 was in
a very luminous high state that resembled the outbursts of X-ray transients
with black hole primaries. At this time, the maxima of the outbursts reached to
K = 7.7, even though Cir X-1 is more than 5 kpc from the Sun! In the early 1980.s,
Cir X-1 was observed to show Type I X-ray bursts that indicated the compact
object was a neutron star. Unfortunately, these events stopped shortly after they
began, only resuming recently. In the 1990.s, however, the X-ray behavior of
Cir X-1 was finally confirmed to be due to accretion onto a neutron star primary.
What makes Cir X-1 especially interesting is the presence of an ultra-relativistic
jet. This jet is seen in both the X-ray and radio, and extends to parsec scales.
There is also evidence that this jet is precessing. If true, then Cir X-1 is
the neutron star counterpart to the unusual high mass X-ray binary system SS433
(where the compact primary is a black hole). We propose to obtain PACS + SPIRE
photometry of Cir X-1 both in outburst, and during quiescence, to identify the
dominant emission processes that occur during these phases. These observations
will allow us to determine if the outbursts are due to a synchrotron jet that simply
turns on during outburst or, alternatively, whether the jet is always present,
but precesses across our line-of-sight once every 16 d. Precessing jets are seen in
pre-main sequence stars, other X-ray binaries, and AGN. Given its extensive
observational history, Cir X-1 is the ideal source for understanding the processes
responsible for launching relat...ivistic jets. Our program requests 2.5 hr of Herschel
Publication Herschel Observations of Circinus X-1 during Outburst and Quiescence . Harrison Thomas E. et al. . The Astronomical Journal, Volume 148, Issue 1, article id. 22, 19 pp. (2014). . 148 . 10.1088\/0004-6256\/148\/1\/22 . 2014AJ....148...22H ,
Instrument PACS_PacsPhoto_largeScan, SPIRE_SpirePhoto_small
Temporal Coverage 2012-09-10T15:33:43Z/2012-10-01T16:52:05Z
Version SPG v14.2.0
Mission Description Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
Creator Contact https://support.cosmos.esa.int/h®erschel/
Date Published 2013-04-01T16:33:10Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, 2013, Unraveling The Outburst And Quiescent Emission Properties Of The Enigmatic Binary Cir X-1, SPG v14.2.0, European Space Agency, https://doi.org/10.5270/esa-30zenhb