Cannot find file /Users/scenko/PROPOSALS/hst/cy22/TDF/tdf-p1.pdf 0 Assigned ID: 521 ----- Attempting Submission 1 (Fri Apr 11 15:15:04 GMT 2014) ----- This target is not used in this proposal. ORBITAL VISIBILITY OVERRUN FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser ORBITAL VISIBILITY OVERRUN FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser v4: New observing window for visit 01. v4: Triggering observations of iPTF15af (Visit 4 only [STIS spectroscopy] for the time being) v4: Triggering observations of ASASSN-15oi (Visits 02, 03, and 07) v3: Triggering observations of ASASSN-14li (Visit 01 only - STIS spectroscopy) v2: Changed WFC3/UVIS filter to F606W (to match original Phase I proposal) v1: I emailed my contact scientist about the details of the STIS observations, but have not heard back yet. This is not a concern, since the Phase II is just a placeholder for ToO observations, but I wanted to submit the Phase II because I may only be in erratic email contact before the Phase II deadline. -1844256559 ----- Attempting Submission 1 (Wed Jul 23 03:53:45 GMT 2014) ----- ----- Attempting Submission 2 (Wed Jul 23 14:34:47 GMT 2014) ----- ----- Attempting Submission 3 (Thu Dec 11 02:32:42 GMT 2014) ----- ----- Attempting Submission 4 (Thu Dec 18 17:59:40 GMT 2014) ----- ----- Attempting Submission 5 (Tue Feb 10 16:25:05 GMT 2015) ----- ----- Attempting Submission 6 (Sat Sep 12 16:21:53 GMT 2015) ----- Since the observations are placeholders for a ToO, I did not include ETC calculations (these will need to be updated with the details for the specific sources). When a star passes within the sphere of disruption of a massive black hole, tidal forces will overcome self-gravity and unbind the star. While approximately half of the stellar debris is ejected at high velocities, the remaining material remains bound to the black hole and accretes, resulting in a luminous, long-lived transient known as a tidal disruption flare (TDF). Aside from serving as a unique laboratory for accretion physics, TDFs offer the hope of measuring black hole masses in galaxies much too distant for resolved kinematic studies. In the simplest analytic models, the black hole mass should scale as dt^2, where dt is the time delay between the disruption and the start of the flare. Two primary factors have so far limited precise black hole mass estimates from current TDF searches: 1) The difficulty of distinguishing a bona fide TDF from the many other transients that can occur in galactic nuclei; 2) Determing the nature of the disrupted star from the observed electromagnetic signal (in particular the presence or absence of H in optical spectra). Here we request non-disruptive ToO spectra of two nearby TDF candidates in the UV with STIS. Our objectives are to search for unique "smoking gun" signatures of the tidal disruption process, and to constrain the geometry and composition of the newly formed accretion disk (and hence the disrupted star). Much like type Ia supernovae, these observations will furthermore serve as a cornerstone for future high-redshift TDF discoveries by LSST, where the rest-frame UV emission is redshifted into the optical bandpass. We request non-disruptive ToO HST observations of two (2) nearby (z <~ 0.3) candidate tidal disruption flares (TDFs) in Cycle 22 or 23. In order to avoid triggering on false positives (i.e., supernovae, AGN outbursts), we require the following (strict) criteria be met in order to trigger our program: - Detection of an optically variable source astrometrically consistent with the nucleus of a resolved galaxy. - Evidence of an absence of previous AGN activity, either photometrically (i.e., through a constant light curve in the historical PTF database) and/or spectroscopically (i.e., a spectrum that is inconsistent with an AGN or LINER). - High luminosity (M <~ -19 mag), with a blue, thermal spectrum, and a slow temporal evolution (weeks to months), to distinguish from core-collapse supernovae. - Resides in a nearby (z <~ 0.3) galaxy (so that we are sampling rest-frame UV with our STIS spectra). - UV detection with the Swift satellite (to ensure limited host extinction, and also for MAMA safety considerations). Our principle objective is to obtain UV (1200-3000 A) spectra of our TDF candidates around maximum light, as this is a region inaccessible from the ground, and we expect unique signatures in this bandpass. We note that these observations are entirely unique to HST -- the Swift grism is neither sufficiently sensitive nor sufficiently high resolution to conduct such observations. As our primary objective (and the bulk of our time request) is dedicated to UV science, we consider this proposal appropriate for the UV initiative. While the exact details of our source cannot be known at the moment, we can use PS1-10jh and previous PTF discoveries as templates to plan our observation. We assume an r-band magnitude around peak of ~ 20 (note that PTF discoveries will be limited to sources approximately this magnitude or brighter, as the survey limit is r <~ 21 mag), a blackbody spectrum with T ~ 1e4 K, and little to no host extinction (the requirement of a Swift UV detection will limit us to at most lightly extincted sight lines). Inputting this SED into the online exposure time calculator, we find we can achieve the largest SNR in the near-UV using STIS with the NUV-MAMA detector and the G230L (1570-3180 A) grating. We assume our targets are visible for 54 minutes each orbit. After including overheads for guide-star acquisition (6 min for the first orbit, 4 min for the second orbit), target acquisition (~ 8 min for an extended source, no peak-up required for 0.2" slit width), and wavelength calibration (4 min per orbit), we find that we can obtain 80 min of integration time (36 min in the first orbit, 44 in the second) with a two-orbit visit. According to the exposure time calculator, we would expect a SNR per resolution element >= 10 for the range from 1650-3000 A for the continuum emission. This should allow us to easily detect strong (W >= 1 A) absorption lines. Simple CLOUDY models of an accretion disk of solar composition also suggest we should be able to detect at least emission lines of Mg II and C III at these wavelengths (depending on the exact redshift of the source). In the far UV, we have compared the throughput possible with both COS (G140L grating) and STIS (G140L grating) and find that they are roughly comparable. To enable the possibility of executing our spectroscopic observations in a single visit, as well as enable some amount of subtraction of the surrounding host galaxy, we have chosen STIS with the FUV-MAMA detector. Using similar overheads as above, with three (3) orbits we can obtain ~ 125 min of exposure time with this setup. Using the exposure time calculator, this implies a SNR >= 10 over the range from 1200-1700 A for the continuum. Here we should be most sensitive to C IV, Si IV, and, most importantly, Ly-alpha (both in emission and absorption). In addition to spectroscopy, we also request three (3) orbits of WFC3 imaging of each source. We have chosen WFC3 because of its finer pixel scale (for astrometry). The first epoch should be obtained near peak (though it need only coincide with the UV spectroscopy within ~ 2 weeks or so). Here we will obtain a strong detection of the transient emission in the F606W filter: we choose a redder (than UV) filter to ensure a sufficient number of sources for astrometric alignment. This can then be used for precise astrometry to ensure that the transient is indeed located in the host galaxy nucleus (following host subtraction). Assuming standard overheads and dither patterns, a source with the characteristics described above (r = 20 mag, T = 5e4K) will be detected with SNR > 100. Given the brightness of the source, we should also have time to image in a second filter even in just one orbit, in which case we will select a broadband UV option (e.g., F225W). Note that we may need to apply a post flash to avoid charge transfer issues in this case. Finally, at late times (> 6 months post-peak), when the transient emission has significantly faded, we will obtain a single epoch of reference imaging of the host galaxy. 1 orbit will be detected to WFC3-UVIS imaging in the same filters to use for template subtraction (and precise astrometry), while the other will be obtained with the NIR channel (F160W) to enable the most precise possible bulge-disk decomposition for the host. Our past experience with this technique implies we can achieve an astrometric precision of < 10 mas in the transient location, while any galaxy with M_BH >~ 1e5 Msun at z <~ 3 will be bright enough to measure the bulge luminosity in a single orbit of F160W imaging. Our total HST request then comes to 16 orbits of HST observations (5 STIS + 3 WFC3 per target). We emphasize that due to the slowly evolving nature of these transients, we do not require disruptive ToO observations, but can instead obtain spectra at maximum light with a time delay of at least three weeks. UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE 12 false true false false SUPPORTED EXT-STAR NUCLEUS J2000 EXT-STAR ACCRETION DISK NUCLEUS J2000 EXT-STAR ACCRETION DISK NUCLEUS J2000 Long-lived, thermal transient from nucleus of non-active galaxy Long-lived, thermal transient from nucleus of non-active galaxy STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/FUV-MAMA Spectroscopic No No G140L 1425 WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F225W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F225W WFC3/IR Imaging No No F160W STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/FUV-MAMA Spectroscopic No No G140L 1425 WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F225W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F225W WFC3/IR Imaging No No F160W POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 1 false POS-TARG DITHER 0.605 LINE false false 3 41.788 WFC3-IR-DITHER-LINE-3PT 2 false 1442073901024 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. /Users/scenko/Desktop/OP-cache/tc-v01.xml 1420877685000 288.8490529753127 (Tic-Visit :proposal-id 13853 :visit-id "01" :proposal-version -1 :trans-version "20150609" :date "12-Sep-2015 12:05:00.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 191856 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13853 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13853 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2805 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3221 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2916 :al-overhead-at-end 198 :internal-dur-at-end 319 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3221 :pcs-gap 0 ) true 2 0 Triggering based on detection of tidal disruption candidate ASASSN-14li. 1442072866632 Timing link suitability includes constraints ([03 After 02 by 180.0 to 365.0 days]) The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. /Users/scenko/Desktop/OP-cache/tc-v02.xml (Tic-Visit :proposal-id 13853 :visit-id "02" :proposal-version -1 :trans-version "20150609" :date "12-Sep-2015 11:47:46.0" :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 1443744 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13853 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13853 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2895 :al-overhead-at-end 122 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) true 1 0 Slow ToO TDF trigger 1442072855957 Timing link suitability includes constraints ([03 After 02 by 180.0 to 365.0 days]) The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. /Users/scenko/Desktop/OP-cache/tc-v03.xml (Tic-Visit :proposal-id 13853 :visit-id "03" :proposal-version -1 :trans-version "20150609" :date "12-Sep-2015 11:47:35.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2279376 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13853 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13853 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2895 :al-overhead-at-end 122 :internal-dur-at-end 31 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "03" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2863 :al-overhead-at-end 0 :internal-dur-at-end 462 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) true 2 0 Host galaxy observations for TDF candidate 1. 1442073933758 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. /Users/scenko/Desktop/OP-cache/tc-v04.xml 1425775995000 110.71985498730248 (Tic-Visit :proposal-id 13853 :visit-id "04" :proposal-version -1 :trans-version "20150609" :date "12-Sep-2015 12:05:32.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 452864 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13853 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13853 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2839 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "04" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2950 :al-overhead-at-end 85 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "04" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2950 :al-overhead-at-end 198 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "04" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2950 :al-overhead-at-end 198 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "04" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2950 :al-overhead-at-end 198 :internal-dur-at-end 319 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) true 5 0 Slow ToO for TDF candidate 2. 1442074068774 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. /Users/scenko/Desktop/OP-cache/tc-v07.xml (Tic-Visit :proposal-id 13853 :visit-id "07" :proposal-version -1 :trans-version "20150609" :date "12-Sep-2015 12:07:47.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 452864 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13853 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13853 :visit-id "07" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2839 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "07" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2950 :al-overhead-at-end 85 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "07" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2950 :al-overhead-at-end 198 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "07" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2950 :al-overhead-at-end 198 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "07" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2950 :al-overhead-at-end 198 :internal-dur-at-end 319 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) true 5 0 Slow ToO for TDF candidate 2. 1442074596888 Timing link suitability includes constraints ([06 After 05 by 180.0 to 365.0 days]) The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. /Users/scenko/Desktop/OP-cache/tc-v05.xml (Tic-Visit :proposal-id 13853 :visit-id "05" :proposal-version -1 :trans-version "20150609" :date "12-Sep-2015 12:16:36.0" :trans-errors '(:WARNINGS 1 :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 1443744 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13853 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13853 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2889 :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 3210 :pcs-gap 0 ) true 1 1 Slow ToO for TDF candidate 2. 1442074599101 Timing link suitability includes constraints ([06 After 05 by 180.0 to 365.0 days]) The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. /Users/scenko/Desktop/OP-cache/tc-v06.xml (Tic-Visit :proposal-id 13853 :visit-id "06" :proposal-version -1 :trans-version "20150609" :date "12-Sep-2015 12:16:38.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2279376 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13853 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13853 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2889 :al-overhead-at-end 116 :internal-dur-at-end 31 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13853 :visit-id "06" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2863 :al-overhead-at-end 0 :internal-dur-at-end 462 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) true 2 1 Host galaxy observations for TDF candidate 2.