Science Keywords: Select from 2 to 5 items. 0 Assigned ID: 620 ----- Attempting Submission 1 (Wed Dec 12 14:42:09 GMT 2018) ----- Joint XMM I implemented some updates following the suggestions of our contact scientist Sylvia Baggett. 223403159 ----- Attempting Submission 1 (Thu Feb 28 02:45:24 GMT 2019) ----- ----- Attempting Submission 2 (Mon Mar 18 19:31:22 GMT 2019) ----- The nearby, middle-aged neutron star PSR B1055-52, one of the so-called Three Musketeers, has been observed once by XMM-Newton in 2000 resulting in a detailed phase-resolved spectral analysis. Chandra observations in 2012 show spectral changes and an apparent >30% flux decrease with respect to the 2000 XMM-Newton observation. These changes are too large to be due to cross-calibration problems. We propose new XMM-Newton observations to probe the apparent spectral changes. Using a better suited instrument mode than the 2000 observations, we will also be able to measure more accurately the magnetospheric spectral component and relate it to the radio and gamma-ray pulse profiles. Furthermore, we will search for phase-dependent absorption features in the new epoch data. The goal of the HST observation in this joint HST/XMM project is to obtain measurements of the pulsar flux in two NIR bands (F110W, F160W). The scheduling is independent from XMM-Newton scheduling. The pulsar is expected to be very faint, and it is close (4.8 arcsec separation) to a bright star. Therefore, we apply ORIENT constraints to avoid diffraction and bleeding spikes. We further employ the STEP-readout mode for a better dynamical exposure coverage that will help to minimize persistence (we cannot avoid peristence at various locations due to many bright objects in the field together with a faint target). We also use a small dither pattern (offsets according to WIDE-3POS-TARGs in Instrument Science Report WFC3 2016-14) aiming to sample the PSF as good as possible. While not the main goal, we will look for extended emission around the position of the pulsar. B. Posselt has experience with WFC3/IR observations, data reduction and analysis. G. Pavlov has broad HST experience with NICMOS, WFPC2, COS, STIS, ACS and WFC3. Stellar Physics 6 false false false false false false false SUPPORTED STAR PULSAR NO J2000 J2000 WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F160W 1552937050598 /tmp/OPVisit3272201162181831417.xml The scheduling data was generated by CASM 27.0. CASM was run in Phase II mode. There is a H=12.3 star a spatial separation of 4.8arcsec and PA=325.7 degree from the target. In order to avoid bleeding and diffraction spikes we chose ORIENT constraints. (Tic-Visit :proposal-id 15676 :visit-id "01" :proposal-version -1 :trans-version "20181130" :date "18-Mar-2019 15:24:10.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1427536 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15676 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15676 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2996 :al-overhead-at-end 0 :internal-dur-at-end 595 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) true 1 0