Science Keywords: Select from 3 to 5 items. 0 Assigned ID: 741 ----- Attempting Submission 1 (Fri Apr 11 19:59:44 GMT 2014) ----- The ATP shows an error: Only 2 keywords (Neutron Stars and Pulsars, Evolution) were chosen instead of 3-5. Unfortunately, all the other keywords in the list are not relevant to our proposal. We were advised by the Helpdesk (Brett Blacker) to submit the proposal as is. I added POS-TARGs in Visits 04 and 05 to move the targets towards Amplifier C to mitigate CTE effects. I also added a stence to the Observing Description. -1490863680 ----- Attempting Submission 1 (Fri Jul 18 12:34:14 GMT 2014) ----- HST Phase II Proposal 13783 (APT_oldpsr_phase2_shadow_filled.apt) successfully submitted. ----- Attempting Submission 2 (Fri Oct 17 19:30:45 GMT 2014) ----- Thermal evolution of old neutron stars We propose the first observational study of the thermal evolution of old neutron stars (NSs) through far-UV observations of three nearby pulsars in the age range from 17 Myr to 6 Gyr. The cooling history of younger NSs is being mapped out in the X-rays, providing important information on the properties of the super-dense matter in the NS interiors. However, only one old NS, millisecond PSR J0437-4715, has so far revealed its thermal emission, which has been detected with HST in the far-UV. The observed high temperature of about 1.5*10^5 K unavoidably requires a heating mechanism to operate in the old NS interiors. Two possible heating mechanisms have been identified, but their relative importance and parameters, which depend on poorly understood properties of the NS matter, are currently unclear. The proposed program will discriminate between the competing heating models and help constrain the properties of matter under extreme physical conditions, such as neutron and proton superfluidity and frictional forces between the superfluid vortices and the crustal solid. Observations of the far-UV surface emission of old NSs, undetectable from the ground, is the only way to establish their long-term thermal evolution (cooling curves) and so probe the cooling/heating mechanisms and the properties of matter at super-high densities. Therefore, the UV capabilities of the HST offer a unique opportunity to carry out such a study, which will be a long-lasting legacy of HST. To measure the temperatures for the chosen sample of old pulsars, we will image the targets with the ACS/SBC detector, the most sensitive detector in the FUV range. To increase the number of souce counts and eliminate the contribution of the Ly-alpha geocoronal emission, we will employ the F125LP filter (1250 - 1700 A) with the SHADOW orbit requirement. We have checked that the shorter SHADOW F125LP exposures yield a larger SNR than longer exposures without the SHADOW requirement with any other SBC filter thanks to the lower air-glow background. We will fill the non-shadow parts of the SHADOW obits with F140LP (1400 - 1700 A) exposures; this narrower filter is used to cut off the geocoronal oxygen lines, which make no contribution in the shadow parts. The brightness temperatures will be deduced from the measured FUV fluxes. The spectral flux Fnu is proportional to T * nu^2 * (R/d)^2 * 10^{-0.4*Anu} in the Rayleigh-Jeans regime, where R is the NS radius as seen by a distant observer (the radii should be similar for all NSs, for a given EOS and similar masses), d is the distance, and Anu is the extinction, which can be inferred from the radio pulsar dispersion measure and the hydrogen column density found in the X-ray observations. For the exposure time estimates, we require the detection limits to be slightly lower than the values predicted by realistic heating models for the corresponding pulsar ages. In the cases where a non-negligible contribution from the magnetospheric emission is possible, we assume the FUV flux close to the conservative lower limit on the magnetospheric flux, because deeper observations would not provide tighter constraints on the thermal emission. We calculated the exposure times needed for detection of the FUV fluxes with the aid of ACS ETC, requiring the detection at the SNR = 4 - 5 level in the 0.1'' radius aperture, close to optimal one for very faint targets. These calculations showed that we will need 4 orbit exposures for the pulsars J2144-3933 and J2124-3358, and a 3 orbit exposure for PSR B0950-08. To reduce the dark current instrumental background, which starts growing dramatically at about 3 hours after turning the SBC on because of increasing instrument temperature, we request 2 visits (of 1 or 2 orbits duration) for each of the targets, and request to schedule the visits after the SBC has been off for a while and cooled down. To evaluate the contribution of the magnetospheric spectrum, we will measure the fluxes of the pulsars (except for B0950+08, the only one in our sample that has already been detected with HST) with the broad WFC3/UVIS F475X filter (3800 - 6000 A), which provides the optimal trade-off between the width and sensitivity. Using the ETC, we found that one orbit per target would suffice to obtain useful limits. To have enough stars for precise astrometry, we will image the field on the entire UVIS detector. To mitigate CTE effects on our very faint targets, we move them towards ampifier C, close to the center of UVIS2-C512C subarray. We will use the WFC3-UVID-DITHER-BOX pattern in each of the 2 orbits. HOT STARS Default false true false false false SUPPORTED STAR PULSAR J2000 J2000 STAR PULSAR J2000 J2000 STAR PULSAR J2000 J2000 ACS/SBC Imaging No No F140LP ACS/SBC Imaging No No F140LP ACS/SBC Imaging No No F140LP WFC3/UVIS Imaging No No F475X WFC3/UVIS Imaging No No F475X POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 2 false The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. /tmp/OPVisit1806487011824747793.xml Since the target is very faint, we need the SBC to be cool during the observation to minimize the dark current. Therefore, we request to schedule the visit after the SBC has been off for a while and cooled down. (Tic-Visit :proposal-id 13783 :visit-id "01" :proposal-version -1 :trans-version "20140605" :date "17-Oct-2014 15:22:01.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "28" :si-bright-earth-limb-angle 20.0 :data-volume 74064 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13783 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13783 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2598 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset 0 :dark-utilization 1920 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3278 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13783 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2598 :al-overhead-at-end 0 :internal-dur-at-end 117 :dark-offset 0 :dark-utilization 1919 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3278 :pcs-gap 0 ) true 2 0 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. /tmp/OPVisit8541086259669021256.xml Since the target is very faint, we need the SBC to be cool during the observation to minimize the dark current. Therefore, we request to schedule the visit after the SBC has been off for a while and cooled down. (Tic-Visit :proposal-id 13783 :visit-id "06" :proposal-version -1 :trans-version "20140605" :date "17-Oct-2014 15:22:03.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "28" :si-bright-earth-limb-angle 20.0 :data-volume 74064 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13783 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13783 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2598 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset 0 :dark-utilization 1920 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3278 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13783 :visit-id "06" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2598 :al-overhead-at-end 0 :internal-dur-at-end 117 :dark-offset 0 :dark-utilization 1919 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3278 :pcs-gap 0 ) true 2 0 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. /tmp/OPVisit4497517007789386389.xml Since the target is very faint, we need the SBC to be cool during the observation to minimize the dark current. Therefore, we request to schedule the visit after the SBC has been off for a while and cooled down. (Tic-Visit :proposal-id 13783 :visit-id "02" :proposal-version -1 :trans-version "20140605" :date "17-Oct-2014 15:22:04.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "28" :si-bright-earth-limb-angle 20.0 :data-volume 37040 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13783 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13783 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2571 :al-overhead-at-end 0 :internal-dur-at-end 77 :dark-offset 0 :dark-utilization 1917 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. /tmp/OPVisit1824028385695514530.xml Since the target is very faint, we need the SBC to be cool during the observation to minimize the dark current. Therefore, we request to schedule the visit after the SBC has been off for a while and cooled down. (Tic-Visit :proposal-id 13783 :visit-id "07" :proposal-version -1 :trans-version "20140605" :date "17-Oct-2014 15:22:04.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "28" :si-bright-earth-limb-angle 20.0 :data-volume 74064 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13783 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13783 :visit-id "07" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2571 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset 0 :dark-utilization 1917 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13783 :visit-id "07" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2571 :al-overhead-at-end 0 :internal-dur-at-end 117 :dark-offset 0 :dark-utilization 1919 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) true 2 0 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. /tmp/OPVisit918978507437334351.xml Since the target is very faint, we need the SBC to be cool during the observation to minimize the dark current. Therefore, we request to schedule the visit after the SBC has been off for a while and cooled down. (Tic-Visit :proposal-id 13783 :visit-id "03" :proposal-version -1 :trans-version "20140605" :date "17-Oct-2014 15:22:05.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "28" :si-bright-earth-limb-angle 20.0 :data-volume 74064 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13783 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13783 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2586 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset 0 :dark-utilization 1919 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13783 :visit-id "03" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2588 :al-overhead-at-end 0 :internal-dur-at-end 117 :dark-offset 0 :dark-utilization 1913 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) true 2 0 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. /tmp/OPVisit3651380659341345680.xml Since the target is very faint, we need the SBC to be cool during the observation to minimize the dark current. Therefore, we request to schedule the visit after the SBC has been off for a while and cooled down. (Tic-Visit :proposal-id 13783 :visit-id "08" :proposal-version -1 :trans-version "20140605" :date "17-Oct-2014 15:22:06.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "28" :si-bright-earth-limb-angle 20.0 :data-volume 74064 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13783 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13783 :visit-id "08" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2586 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset 0 :dark-utilization 1919 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13783 :visit-id "08" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2588 :al-overhead-at-end 0 :internal-dur-at-end 117 :dark-offset 0 :dark-utilization 1913 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) true 2 0 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. /tmp/OPVisit1820083366041622314.xml (Tic-Visit :proposal-id 13783 :visit-id "04" :proposal-version -1 :trans-version "20140605" :date "17-Oct-2014 15:22:07.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1154992 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13783 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13783 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2944 :al-overhead-at-end 116 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3278 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. /tmp/OPVisit220327254006526788.xml (Tic-Visit :proposal-id 13783 :visit-id "05" :proposal-version -1 :trans-version "20140605" :date "17-Oct-2014 15:22:08.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1154992 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13783 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13783 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2924 :al-overhead-at-end 116 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) true 1 0