|Proposal Number||Subject Category||PI Name||Chandra Time||Title|
|13200002||Stars and WD||Katja Peppenhaeger||tau Boo's Magnetic Polarity Switch in X-rays - continued monitoring|
|13300001||WD Binaries and CV||Wolfgang Pietsch||Resolving short supersoft source states of optical novae in the core of M31|
|13400003||BH and NS Binaries||Paolo Soleri||An X-ray look at the first head-trail nebula in an X-ray binary|
|13500004||SN, SNR and Isolatated NS||Nanda Rea||Testing the magnetar model with the first low-B soft gamma repeater|
Subject Category: Stars and WD
Proposal Number: 13200002
Title: Tau Boo's Magnetic Polarity Switch in X-rays - continued monitoring
PI Name: Katja Poppenhaeger
tau Boo is the first star other than the Sun which has been observed to have a global magnetic field with switching polarity. In contrast to the Sun, tau Boo s magnetic cycle has a duration of only two years. We propose to continue monitoring the star during this AO with XMM-Newton for a total of 32 ks as well as with Chandra for a total of 10 ks to gain more insight into the stellar activity cycle by comparing X-ray luminosities and coronal temperatures derived from the CCD spectra to the chromospheric activity profile and the magnetic field configuration of tau Boo.
Subject Category: WD Binaries and CV
Proposal Number: 13300001
Title: Resolving short supersoft source states of optical novae in the core of M31
PI Name: Wolfgang Pietsch
We propose to continue the monitoring of the M31 core with 5x23ks XMM-Newton EPIC and 5x20ks Chandra HRC-I observations equally distributed from Nov 2011 to mid Feb 2012 to determine additional light curves for short SSS states of optical novae. SSS states with <100 d duration indicate accreting massive white dwarfs (WDs). They are proposed as SN Ia progenitors and determining their frequency is very important. We will correlate detected sources with novae from optical monitoring. With a nova rate in the field of ~38/yr and SSS states lasting from weeks to years we will follow light curves of many novae. Durations of the nova SSS state will allow us to constrain envelope and WD masses. We will also monitor time variability of ~200 M31 X-ray sources (mostly XRBs).
Subject Category: BH and NS Binaries
Proposal Number: 13400003
Title: An X-ray look at the first head-trail nebula in an X-ray binary
PI Name: Paolo Soleri
Head-tail trails are a common feature in active galactic nuclei and pulsar bow-shocks. Heinz et al. (2008) suggested that also X-ray binaries, being jet sources moving with high velocities in dense media, can leave trails of highly ionized plasma that should be detectable at radio frequencies. During bservations of faint-persistent X-ray binaries, we discovered an optical nebula around the X-ray binary SAX J1712.6-3739, consisting of a bow-shock ring-like nebula in front of the binary and two trails originating close to it. This is the first detection of such structure in a X-ray binary and it opens a new sub-field in the study of these objects. Observations with XMM-Newton and Chandra are now needed to investigate the properties of the surrounding nebula.
Subject Category: SN, SNR and Isolated NS
Proposal Number: 13500004
Title: Testing the magnetar model with the first low-B soft gamma repeater
PI Name: Nanda Rea
Soft gamma repeaters (SGRs) are part of a rapidly increasing group of x-ray sources exhibiting sporadic short bursts and outbursts, believed to be neutron stars powered by extreme magnetic fields. We have recently discovered an SGR with a low magnetic field, SGR0418+5729, discovered in outburst after it emitted bursts similar to those of magnetars. X-ray observations show that its dipolar magnetic field cannot be greater than 7.5x10^12,Gauss, well in the range of ordinary radio pulsars. We ask for a joint XMM/Chandra monitoring of the first low-B magnetar,in order to have a final measure or a deeper upper limit of its period derivative, hence of it surface dipolar B field.