9122( 2) - 02/15/01 15:53 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9122 Version: 2 Check-in Date: 15-Feb-2001 15:52:41 1.Proposal Title: The Physics of X-Ray/Optical Jets ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Claudia Urry Space Telescope Science Institute CoI: Mr. Fabrizio Tavecchio Osservatorio Astronomico di Brera N CoI: Prof. Laura Maraschi Osservatorio Astronomico di Brera N CoI: Dr. Joseph Pesce Eureka Scientific N CoI: Prof. John Wardle Brandeis University N CoI: Mr. Chi Cheung Brandeis University N CoI: Prof. Rita Sambruna George Mason University N CoI: Dr. Riccardo Scarpa European Southern Observatory N ------------------------------------------------------------------------------------ 5. Abstract An important new probe of the physics of large-scale radio jets is possible with the discovery of resolved X-ray/optical jets. The optical emission comes from high energy electrons, which have short radiative lifetimes and so pinpoint particle acceleration sites. Spectral energy distributions of knots in two jets suggest the X -rays come from lower energy electrons inverse-Compton scattering the (beamed) cosmic microwave background. This requires the jet to be still relativistic on kiloparsec scales (out to ~1 Mpc for the high-redshift jets.). This model robustly constrains both the bulk relativistic speed and the minimum electron energy in the jet, which together determine the total jet power. To probe jet energetics and physics generally, and to test the ``Compton/CMB'' interpretation specifically, we propose deep HST imaging of three X-ray/optical jets (PKS 1127--145, PKS 0637--752, 3C 371) and one optical jet (PKS 2201+044), plus Chandra observations of the latter two. The multiwavelength spectra of individual knots differ significantly, as does one jet from another, indicating the need for detailed high- resolution study of more than 1 or 2 jets. Along with the well-observed 3C 273 and M 87 jets, the 4 proposed targets are the only known (or likely) nonthermal X-ray jets readily detected with Chandra and HST. ------------------------------------------------------------------------------------ 9122( 2) - 02/15/01 15:53 - [ 2] Observations Description ------------------------ HST Exposure Time Estimates: Three of the four jets have already been detected in the optical, and another three have been detected at X-rays. Scaling the radio, optical and X-ray fluxes using reasonable SEDs (Fig. 2), we can easily estimate the exposure times needed by comparing to existing HST and Chandra data. We verified these times using the exposure time calculators for the appropriate instrument/filter combination, for a signal-to-noise ratio of >~10 in at least 10 bins along the length of the jet (the knots span at least 10 pixels in each case, so jets can be smoothed to improve the signal-to-noise ratio). N.B. For the two nearby targets, the host galaxy is a significant source of ``background,'' and our estimate took this into account; this is more of a problem in the redder filters, hence our emphasis on blue exposures for 3C 371 and PKS 2201+044. For the high redshift quasars, PKS 0637-752 and PKS 1127- -145, the host galaxy surface brightness is negligible and was ignored. Total request: 10 HST orbits for 4 targets, and 80 ks Chandra ACIS-S observations of 2 of these. 3C 371 --- This nearby BL Lac object (z=0.051) has a prominent radio jet with optical 13, 19 and X-ray 14 counterparts. The jet was detected in an F555W WFPC2 image (302 s) as part of our snapshot survey of BL Lac objects 19, 27; there is also a 560- s F702W snapshot image in the archive 11. These observations were done before the 3C 371 jet was discovered 13 and so have less than optimal signal-to-noise ratios, << 1 per pixel (considering the bright host galaxy as background). Three optical knots are detected, each coincident with a bright radio knot; there is a hint of an optical counterpart of the fourth radio knot, but the expected V-band flux (extrapolating from the radio) is about a magnitude fainter than the limit of our observation 19. The proposed 1 orbit of WFPC2 F555W images will go 3-4 times deeper than the existing image (this is a CVZ target), so we can increase the S/N ratios in the three clearly detected knots, detect the fourth knot, and put tight constraints on the multiwavelength SEDs of individual knots. PKS 0637--752 --- The Chandra discovery of an X-ray jet coincident with the known radio jet was surprising, since this is a high-redshift quasar formerly thought to be a point source at optical and X-ray wavelengths. The jet was imaged serendipitously with HST WFPC2 F702W as part of search for Ly-alpha absorbing galaxies near quasars, and so is unfortunately located on the WF chip rather than the higher resolution PC chip. Close examination of the HST image shows faint optical emission coincident with the radio and X-ray knots, although only the first was bright enough to model 3, 26. A deeper exposure with HST would permit analysis of more than one jet knot and a second filter would provide spectral information, which is enormously important to the modeling. (The optical band is roughly where the synchrotron emission curves sharply.) The proposed 2 orbits WFPC2 F702W will roughly double the signal-to-noise ratio in the combined image, and 2 orbits STIS CCD F28x50LP will go deeper (because of the broad filter) and give a red color (when combined with the narrow F702W filter), where the jet should be brighter according to our best models (Fig. 2). PKS 2201+044 --- This nearby (z=0.028) BL Lac object has an optical jet discovered in our HST snapshot survey 19. One faint optical knot was visible in the 610-s WFPC2 F702W image, precisely coincident with the brightest radio knot at 5 GHz 9. Our goal is to detect optical counterparts for the other radio knots; they should be a few times fainter than the one detected knot if the optical flux scales with the radio flux (as expected, since alpha_ro is roughly constant along other known optical jets 20). If the 2201+044 jet is similar to that of 3C 273, its synchrotron spectrum is steep in the optical because of radiative losses; this means the optical spectrum strongly constrains the maximum energy of the radiating electrons. The proposed 2 orbits of WFPC2 F555W will greatly increase the signal-to-noise of the jet in the archival V-band image; the proposed 1 orbit of STIS F28X50LP, where the galaxy ``background'' is weak, will provide the jet color. PKS 1127--145 --- The X-ray detection of this jet with the Chandra ACIS-S instrument was recently reported (in an abstract for the HEAD 2000 meeting 25; these data are not yet public), with 189 photons in 27 ks along the same position angle of the known radio jet 17. This is not totally unexpected given that this is a bright, flat-spectrum radio- loud quasar (z=1.187) with compact VLBI-observed structure and high polarization 23, and it is also an EGRET gamma-ray source with a high estimated Doppler factor 6 --- i.e., it is a typical blazar. There is an old WFPC image in the archive, not useful for our purposes because of spherical aberration. Since this is not (yet) a known optical jet, the proposed HST observation is for the most sensitive filter/detector, 2 orbits with STIS CCD F28X50LP. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- 3C371.0 is a CVZ target. PKS 0637-752 is very close to being a CVZ target. ------------------------------------------------------------------------------------ 9122( 2) - 02/15/01 15:53 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PKS0637-752 GALAXY, QUASAR RA=06H 35M 46.507954S +/- J2000 Z = V = 15.75+/-1.0 0.00015S, DEC=-75D 16' 16.81497" 0.651 +/- 0.00015" Coordinate Source: OTHER_SOURCE Comments: Targeting detection of V=25.70 knot in jet source. 2 PKS0637-752- GALAXY, QUASAR XI-OFF=0.1265"+/- 0.01", ETA- J2000 Z = V = 15.75+/-1.0 POS1 OFF=0.1265"+/- 0.01", FROM 1 0.651 Coordinate Source: OTHER_SOURCE Comments: Targeting detection of V=25.70 knot in jet source. 3 PKS0637-752- GALAXY, QUASAR XI-OFF=0.253"+/- 0.01", ETA- J2000 Z = V = 15.75+/-1.0 POS2 OFF=0"+/- 0.01", FROM 1 0.651 Coordinate Source: OTHER_SOURCE Comments: Targeting detection of V=25.70 knot in jet source. 4 PKS0637-752- GALAXY, QUASAR XI-OFF=0.1265"+/- 0.01", ETA- J2000 Z = V = 15.75+/-1.0 POS3 OFF=-0.1265"+/- 0.01", FROM 1 0.651 Coordinate Source: OTHER_SOURCE Comments: Targeting detection of V=25.70 knot in jet source. 5 PKS1127-14- GALAXY, QUASAR RA=11H 30M 7.745S +/- 0.00043S, J2000 Z = V = 16.9+/-1.0 JET DEC=-14D 49' 16.241" +/- 1.187 0.00043" Coordinate Source: OTHER_SOURCE Comments: Targeting detection of V=24.39 knot in jet source. Position is offset from center of source by 15" at position angle 42 deg. 6 PKS1127-14- GALAXY, QUASAR XI-OFF=0.1265"+/- 0.01", ETA- J2000 Z = V = 16.9+/-1.0 POS1 OFF=0.1265"+/- 0.01", FROM 5 1.187 Coordinate Source: OTHER_SOURCE Comments: Targeting detection of V=24.39 knot in jet source. 7 PKS1127-14- GALAXY, QUASAR XI-OFF=0.253"+/- 0.01", ETA- J2000 Z = V = 16.9+/-1.0 POS2 OFF=0"+/- 0.01", FROM 5 1.187 Coordinate Source: OTHER_SOURCE Comments: Targeting detection of V=24.39 knot in jet source. 8 PKS1127-14- GALAXY, QUASAR XI-OFF=0.1265"+/- 0.01", ETA- J2000 Z = V = 16.9+/-1.0 POS3 OFF=-0.1265"+/- 0.01", FROM 5 1.187 Coordinate Source: OTHER_SOURCE Comments: Targeting detection of V=24.39 knot in jet source. 9 3C371.0 GALAXY, BL LAC, RADIO RA=18H 6M 50.59S +/- 0.01S, J2000 Z = V = 14.2+/-1.0 GALAXY DEC=69D 49' 28.1" +/- 0.05", 0.051 PLATE-ID=01L8 Coordinate Source: HST_IMAGE Comments: Targeting detection of V=23.10 knot in jet source. This is a CVZ target. 10 3C371.0-POS1 GALAXY, BL LAC, RADIO XI-OFF=0.1265"+/- 0.01", ETA- J2000 Z = V = 14.2+/-1.0 GALAXY OFF=0.1265"+/- 0.01", FROM 9, 0.051 PLATE-ID=01L8 Coordinate Source: HST_IMAGE Comments: Targeting detection of V=23.10 knot in jet source. This is a CVZ target. 9122( 2) - 02/15/01 15:53 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 11 3C371.0-POS2 GALAXY, BL LAC, RADIO XI-OFF=0.253"+/- 0.01", ETA- J2000 Z = V = 14.2+/-1.0 GALAXY OFF=0"+/- 0.01", FROM 9, PLATE- 0.051 ID=01L8 Coordinate Source: HST_IMAGE Comments: Targeting detection of V=23.10 knot in jet source. This is a CVZ target. 12 3C371.0-POS3 GALAXY, BL LAC, RADIO XI-OFF=0.1265"+/- 0.01", ETA- J2000 Z = V = 14.2+/-1.0 GALAXY OFF=-0.1265"+/- 0.01", FROM 9, 0.051 PLATE-ID=01L8 Coordinate Source: HST_IMAGE Comments: Targeting detection of V=23.10 knot in jet source. This is a CVZ target. 13 PKS2201+044 GALAXY, BL LAC RA=22H 4M 17.69S +/- 0.01S, J2000 Z = V = 15.2+/-1.0 DEC=04D 40' 2.3" +/- 0.05", 0.028 PLATE-ID=0511 Coordinate Source: HST_IMAGE Comments: Targeting detection of V=24.68 knot in jet source. 14 PKS2201+044- GALAXY, BL LAC XI-OFF=0.1265"+/- 0.01", ETA- J2000 Z = V = 15.2+/-1.0 POS1 OFF=0.1265"+/- 0.01", FROM 13, 0.028 PLATE-ID=0511 Coordinate Source: HST_IMAGE Comments: Targeting detection of V=24.68 knot in jet source. 15 PKS2201+044- GALAXY, BL LAC XI-OFF=0.253"+/- 0.01", ETA- J2000 Z = V = 15.2+/-1.0 POS2 OFF=0"+/- 0.01", FROM 13, PLATE- 0.028 ID=0511 Coordinate Source: HST_IMAGE Comments: Targeting detection of V=24.68 knot in jet source. 16 PKS2201+044- GALAXY, BL LAC XI-OFF=0.1265"+/- 0.01", ETA- J2000 Z = V = 15.2+/-1.0 POS3 OFF=-0.1265"+/- 0.01", FROM 13, 0.028 PLATE-ID=0511 Coordinate Source: HST_IMAGE Comments: Targeting detection of V=24.68 knot in jet source. 9122( 2) - 02/15/01 15:53 - [ 5] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: This source is close to CVZ. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 PKS0637-752 WFPC2 IMAGE PC1 F702W CR-SPLIT=NO 1 40 S ------------------------------------------------------------------------------------------------------------------------------------ 20 PKS0637-752 WFPC2 IMAGE PC1 F702W 1 1200 S ------------------------------------------------------------------------------------------------------------------------------------ 30 PKS0637-752 WFPC2 IMAGE PC1 F702W CR-SPLIT=NO 1 1200 S -POS1 ------------------------------------------------------------------------------------------------------------------------------------ 40 PKS0637-752 WFPC2 IMAGE PC1 F702W 1 1200 S -POS2 ------------------------------------------------------------------------------------------------------------------------------------ 50 PKS0637-752 WFPC2 IMAGE PC1 F702W 1 1200 S -POS3 ------------------------------------------------------------------------------------------------------------------------------------ 60 PKS0637-752 STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO 1 60 S -POS3 CD P ------------------------------------------------------------------------------------------------------------------------------------ 70 PKS0637-752 STIS/C ACCUM F28X50L MIRROR 1 1500 S -POS3 CD P ------------------------------------------------------------------------------------------------------------------------------------ 80 PKS0637-752 STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO 1 1500 S -POS2 CD P ------------------------------------------------------------------------------------------------------------------------------------ 90 PKS0637-752 STIS/C ACCUM F28X50L MIRROR 1 1500 S -POS1 CD P ------------------------------------------------------------------------------------------------------------------------------------ 100 PKS0637-752 STIS/C ACCUM F28X50L MIRROR 1 1600 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 9122( 2) - 02/15/01 15:53 - [ 6] Visit: 02 Visit Priority: Visit Requirements: ORIENT 52D TO 122D ORIENT 232D TO 302D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 PKS1127-14- STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO 1 60 S JET CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PKS1127-14- STIS/C ACCUM F28X50L MIRROR 1 1300 S JET CD P ------------------------------------------------------------------------------------------------------------------------------------ 30 PKS1127-14- STIS/C ACCUM F28X50L MIRROR 1 1300 S POS1 CD P ------------------------------------------------------------------------------------------------------------------------------------ 40 PKS1127-14- STIS/C ACCUM F28X50L MIRROR 1 1300 S POS2 CD P ------------------------------------------------------------------------------------------------------------------------------------ 50 PKS1127-14- STIS/C ACCUM F28X50L MIRROR 1 1400 S POS3 CD P ------------------------------------------------------------------------------------------------------------------------------------ 9122( 2) - 02/15/01 15:53 - [ 7] Visit: 03 Visit Priority: Visit Requirements: CVZ On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 3C371.0 WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 40 S ------------------------------------------------------------------------------------------------------------------------------------ 20 3C371.0 WFPC2 IMAGE PC1 F555W 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 30 3C371.0-POS WFPC2 IMAGE PC1 F555W 1 1000 S 1 ------------------------------------------------------------------------------------------------------------------------------------ 40 3C371.0-POS WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 800 S 2 ------------------------------------------------------------------------------------------------------------------------------------ 50 3C371.0-POS WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 800 S 3 ------------------------------------------------------------------------------------------------------------------------------------ 9122( 2) - 02/15/01 15:53 - [ 8] Visit: 04 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 PKS2201+044 WFPC2 IMAGE PC1 F555W 1 40 S ------------------------------------------------------------------------------------------------------------------------------------ 20 PKS2201+044 WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 1100 S ------------------------------------------------------------------------------------------------------------------------------------ 30 PKS2201+044 WFPC2 IMAGE PC1 F555W CR-SPLIT=NO 1 1100 S -POS1 ------------------------------------------------------------------------------------------------------------------------------------ 40 PKS2201+044 WFPC2 IMAGE PC1 F555W 1 1000 S -POS2 ------------------------------------------------------------------------------------------------------------------------------------ 50 PKS2201+044 WFPC2 IMAGE PC1 F555W 1 1000 S -POS3 ------------------------------------------------------------------------------------------------------------------------------------ 60 PKS2201+044 STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO 1 36 S -POS3 CD P ------------------------------------------------------------------------------------------------------------------------------------ 70 PKS2201+044 STIS/C ACCUM F28X50L MIRROR 1 800 S -POS3 CD P ------------------------------------------------------------------------------------------------------------------------------------ 80 PKS2201+044 STIS/C ACCUM F28X50L MIRROR 1 900 S -POS2 CD P ------------------------------------------------------------------------------------------------------------------------------------ 90 PKS2201+044 STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO 1 800 S -POS1 CD P ------------------------------------------------------------------------------------------------------------------------------------ 9122( 2) - 02/15/01 15:53 - [ 9] Summary Form for Proposal 9122 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1 F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 52D TO 122D ORIENT 232D TO 302D CVZ ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F702W MIRROR F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names PKS0637-752 PKS0637-752-POS1 PKS0637-752-POS2 PKS0637-752-POS3 PKS1127-14-JET PKS1127-14-POS1 PKS1127-14-POS2 PKS1127-14-POS3 3C371.0 3C371.0-POS1 3C371.0-POS2 3C371.0-POS3 PKS2201+044 PKS2201+044-POS1 PKS2201+044-POS2 PKS2201+044-POS3 ------------------------------------------------------------------------------------------------------------------------------------