Probing Weak Intergalactic Absorption with Flaring Blazar Spectra

resubmission with minor edits Assigned ID: 598 ----- Attempting Submission 1 (Fri Feb 25 20:24:17 GMT 2011) ----- HST Phase I Proposal 598 (prop_blazar_too.apt) successfully submitted. ----- Attempting Submission 2 (Fri Feb 25 23:37:28 GMT 2011) ----- HST Phase I Proposal 598 (prop_blazar_too.apt) successfully submitted. ToO #2 activated. Generic Target #2 changed to fixed target (blazar 3C66a) and Visit 02 modified accordingly. Visit 02 changed to G130M only due to conflict with cycle 20 GO program. HOPR repeat--visit 04 copy of visit 02 Exposures in visit 04 shortened by 240 seconds for continual visibility through March 2013. ----- Attempting Submission 1 (Fri Jul 08 19:16:09 GMT 2011) ----- ----- Attempting Submission 2 (Tue Apr 03 19:57:24 GMT 2012) ----- HST Phase II Proposal 12612 (blazar_targ1.apt) successfully submitted. ----- Attempting Submission 3 (Tue Apr 03 21:49:33 GMT 2012) ----- HST Phase II Proposal 12612 (blazar_targ1.apt) successfully submitted. ----- Attempting Submission 4 (Wed Apr 04 15:15:23 GMT 2012) ----- ----- Attempting Submission 5 (Tue Aug 28 16:30:38 GMT 2012) ----- HST Phase II Proposal 12612 (12612_p2.2.apt) successfully submitted. ----- Attempting Submission 6 (Wed Aug 29 21:00:28 GMT 2012) ----- ----- Attempting Submission 7 (Mon Oct 15 14:32:08 GMT 2012) ----- ----- Attempting Submission 8 (Mon Oct 15 17:33:34 GMT 2012) ----- All errors are due to "improper use of Generic Target". Probing Weak Intergalactic Absorption with Flaring Blazar Spectra We propose to exploit the flaring states of high- and unknown-redshift blazars to obtain very high S/N > 25 COS spectra in order to study details of the local intergalactic medium (IGM) not accessible for study using the plethora of lower S/N data being obtained. Only with very high S/N spectra is it possible to detect the weakest Ly alpha and metal lines wherein may lie a substantial portion of the cosmic baryons. The numbers of weak OVI absorbers can discriminate between collisionally ionized and photoionized models, as well as determine which of several galactic outflow models best matches the IGM metal enrichment. Most importantly, high S/N spectra plus the featureless UV power-law continuum of blazars facilitates the detection of broad, shallow absorbers ["broad Ly alpha" (BLA) and broad OVI-only absorbers] which uniquely probe the T = 3 x 10^5 - 3 x 10^6 K range in the IGM where many cosmic baryons are predicted to be "hiding." In addition, these same spectra will be used to obtain lower limits on, or estimates of, the redshift for any featureless blazars observed using the foreground Ly-alpha forest absorbers. In some cases weak Lyman alpha emission may also be detected, as was recently discovered for a few well-known low-redshift BL Lac objects using COS spectra. We request up to three *non-disruptive ToOs* to carry out this program in Cycle 19. Ground-based monitoring will select objects flaring to V ~ 13.5 mag for HST observations, out of a set of about 30 monitored blazars. We have selected our targets from several pools of known blazars. The ﬁrst group (12) are objects with known or suggested emission redshifts > 0.3 to maximize the pathlength for weak intergalactic Lyα, O VI, and other important diagnostic lines. The second group (6) are objects known to be simultaneously bright in TeV gamma-rays and with nominal UV ﬂuxes above ~10^−15 erg cm−2 s−1 A−1. All targets have measured GALEX NUV and FUV ﬂuxes and are in regions of moderate to low Galactic extinction. We assume the unreddened continuum in the optical-UV range follows a power-law be- havior of the form fλ ∝ λ−α and determine the slope α from published GALEX NUV/FUV ﬂuxes. These ﬂuxes were obtained simultaneously and their ratio should be insensitive to luminosity variations in the AGN. Observed GALEX UV indices are 0 < α < 2, typical of those seen in detailed UV spectra of BL Lac objects (e.g., Stocke, Danforth & Perlman 2011). All targets will be monitored on the ground by a network of small, optical telescopes (see Coordinated Observations below) with a ~3 day cadence. We estimate optical trigger thresholds for each target based on these power laws and the observed Galactic extinction toward each object. When the optical magnitude indicates that the reddened ﬂux in the far- UV is ~(2−3)e−14 erg cm−2 s−1 A−1, we will activate a non-disruptive ToO observation. The typical magnitude for triggering these observations is V ≤ 13.5. For F1500≈3e−14 erg cm−2 s−1 A−1, we estimate that we can achieve S/N ≈ 25 per resolution element in a single ﬁve-orbit HST visit. The observations will be carried out in both COS/G130M (~2 orbits) and COS/G160M (~3 orbits) using muliple grating central wavelength and FP positions. This is to ensure continuous spectral coverage over the 1132 < λ < 1795 wavelength range and to dither instrumental features (repellor grid wire shadows, gain sag artifacts, etc.) across the spectrum. Two members of the team have extensive experience in this area as members of the COS GTO team. Unfortunately, we cannot guarantee that any particular object will remain above our ﬂare threshold for the 2-4 weeks required for Preferred Scheduling observations (a.k.a. “non- disruptive ToO”). To minimize the chances of a “miss,” we will carefully examine the his- torical variability record for each object and the trend of the ﬂare in progress to predict the duration of a ﬂare. However, even if our chosen blazar has faded somewhat below our F1500≈3e−14 erg cm−2 s−1 A−1 trigger level, we can still obtain very useful data at lower S/N with our planned observations. As a case in point, 1ES 1553+113 was observed in a non-ﬂaring state (3 HST orbits, F1500~1.5e−14, S/N ∼ 15). Danforth et al. (2010) published a study of over 100 intervening absorption lines, including several interesting new OVI absorbers, and constrained the source redshift to 0.3950 ≤ z < 0.45. Even if the objects are not near peak ﬂux during the HST observations, our data (obtained at an above-average ﬂux level) will enable compelling and original science. QUASAR ABSORPTION LINES AND IGM 12 false 0.0 0.0 false false false false SUPPORTED GALAXY BL LAC JET 7C1424+2401 J1427+2347 J2000 F(1300A)~(2.7+/-1.4)e-14 erg cm-2 s-1 Ang-1, R~13.7+/-0.5 GALAXY BL LAC ELLIPTICAL JET QSO RADIO GALAXY This object was generated by the targetselector and retrieved from the NED database. J0222+4302 J2000 F(1500A)~(2.0+-0.5)e-14 erg cm-2 s-1 Ang-1 GALAXY BL LAC ToO (optically-monitored flaring blazar) F(1500A)~3e-14 erg cm-2 s-1 Ang-1 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1300 COS/FUV Spectroscopic No No G130M 1309 COS/FUV Spectroscopic No No G130M 1318 COS/FUV Spectroscopic No No G130M 1327 COS/FUV Spectroscopic No No G160M 1577 COS/FUV Spectroscopic No No G160M 1589 COS/FUV Spectroscopic No No G160M 1600 COS/FUV Spectroscopic No No G160M 1611 COS/FUV Spectroscopic No No G160M 1623 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1300 COS/FUV Spectroscopic No No G130M 1309 COS/FUV Spectroscopic No No G130M 1318 COS/FUV Spectroscopic No No G130M 1327 COS/FUV Spectroscopic No No G160M 1577 COS/FUV Spectroscopic No No G160M 1589 COS/FUV Spectroscopic No No G160M 1600 COS/FUV Spectroscopic No No G160M 1611 COS/FUV Spectroscopic No No G160M 1623 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1300 COS/FUV Spectroscopic No No G130M 1309 COS/FUV Spectroscopic No No G130M 1318 COS/FUV Spectroscopic No No G130M 1327 COS/FUV Spectroscopic No No G160M 1577 COS/FUV Spectroscopic No No G160M 1589 COS/FUV Spectroscopic No No G160M 1600 COS/FUV Spectroscopic No No G160M 1611 COS/FUV Spectroscopic No No G160M 1623 1346171387271 The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. Flaring Blazar ToO #1 (5 orbits) 1334833285000 193.2681625070419 (Tic-Visit :proposal-id 12612 :visit-id "01" :proposal-version -1 :trans-version "20120604" :date "28-Aug-2012 10:29:46.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 1244016 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12612 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12612 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2779 :al-overhead-at-end 0 :internal-dur-at-end 76 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3244 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2876 :al-overhead-at-end 0 :internal-dur-at-end 86 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3244 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2850 :al-overhead-at-end 0 :internal-dur-at-end 48 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3244 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "01" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2888 :al-overhead-at-end 0 :internal-dur-at-end 48 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3244 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "01" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2859 :al-overhead-at-end 0 :internal-dur-at-end 376 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3244 :pcs-gap 0 ) true 5 0 S/N>40 at 50% nominal flux or above (F_1500>1.5e-14). However, if flux is 2x expected level, count rate is still acceptable (COS.ta.196577). S/N>40 at 50% nominal flux or above (F_1500>1.5e-14). However, if flux is 2x expected level, count rate is still acceptable (COS.ta.196577). For F(1500)=3e-14, expect S/N~18 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~18 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. 1346272805940 The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. 3C66A ToO #2 (5 orbits) 1350131137000 207.64647559203797 (Tic-Visit :proposal-id 12612 :visit-id "02" :proposal-version -1 :trans-version "20120604" :date "29-Aug-2012 14:40:05.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 2417872 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12612 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12612 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2967 :al-overhead-at-end 0 :internal-dur-at-end 114 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3064 :al-overhead-at-end 0 :internal-dur-at-end 86 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "02" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3064 :al-overhead-at-end 0 :internal-dur-at-end 86 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "02" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3064 :al-overhead-at-end 0 :internal-dur-at-end 86 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "02" :orbit-number 5 :pcs-time 222 :si-vis-utilization 3064 :al-overhead-at-end 0 :internal-dur-at-end 414 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) true 5 0 S/N>40 at 50% nominal flux or above (F_1500>1.5e-14). However, if flux is 2x expected level, count rate is still acceptable (COS.ta.196577). S/N>40 at 50% nominal flux or above (F_1500>1.5e-14). However, if flux is 2x expected level, count rate is still acceptable (COS.ta.196577). For F(1500)=3e-14, expect S/N~18 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~18 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. 1350322243839 The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. /private/var/folders/qE/qEEx7lkNGYWV9JoYFBG98k+++TI/-Tmp-/OPVisit2705091421556428429.xml HOPR copy of visit 02: 3C66A ToO #2 (5 orbits) Exposures shortened to improve visibility ranges. (Tic-Visit :proposal-id 12612 :visit-id "04" :proposal-version -1 :trans-version "20120604" :date "15-Oct-2012 11:30:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 2243904 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12612 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12612 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2727 :al-overhead-at-end 0 :internal-dur-at-end 76 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "04" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2824 :al-overhead-at-end 0 :internal-dur-at-end 133 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "04" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2824 :al-overhead-at-end 0 :internal-dur-at-end 133 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "04" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2824 :al-overhead-at-end 0 :internal-dur-at-end 133 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "04" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2824 :al-overhead-at-end 0 :internal-dur-at-end 461 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) true 5 0 S/N>40 at 50% nominal flux or above (F_1500>1.5e-14). However, if flux is 2x expected level, count rate is still acceptable (COS.ta.196577). S/N>40 at 50% nominal flux or above (F_1500>1.5e-14). However, if flux is 2x expected level, count rate is still acceptable (COS.ta.196577). For F(1500)=3e-14, expect S/N~18 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~18 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. 1346171397379 The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. Flaring Blazar ToO #3 (5 orbits) (Tic-Visit :proposal-id 12612 :visit-id "03" :proposal-version -1 :trans-version "20120604" :date "28-Aug-2012 10:29:56.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 1261392 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12612 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12612 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2779 :al-overhead-at-end 0 :internal-dur-at-end 76 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "03" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2956 :al-overhead-at-end 0 :internal-dur-at-end 86 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "03" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2890 :al-overhead-at-end 0 :internal-dur-at-end 48 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "03" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2928 :al-overhead-at-end 0 :internal-dur-at-end 48 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12612 :visit-id "03" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2859 :al-overhead-at-end 0 :internal-dur-at-end 376 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) true 5 0 S/N>40 at 50% nominal flux or above (F_1500>1.5e-14). However, if flux is 2x expected level, count rate is still acceptable (COS.ta.196577). S/N>40 at 50% nominal flux or above (F_1500>1.5e-14). However, if flux is 2x expected level, count rate is still acceptable (COS.ta.196577). For F(1500)=3e-14, expect S/N~18 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~18 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate. For F(1500)=3e-14, we expect S/N~16 per resel. Buffer time based on 2x nominal count rate.