Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4331c Report Date: 09-May-96:19:32 Version: ********** Check-in Date: ********** 1.Proposal Title: HOT GAS IN THE DISK AND HALO OF NGC4319 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID INTERSTELLAR MEDIUM GO Sub Category ABSORPTION LINES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Edward B. Jenkins PRINCETON UNIVERSITY U.S.A. ------------------------------------------------------------------------------------ 7. Abstract A bright (V = 15.2) Seyfert 1 galaxy, Mrk 205, will be observed with the G160M mode of GHRS at wavelengths centered on the N V resonance doublet, in an attempt to detect absorption features from hot gas in the disk and halo of a foreground spiral galaxy, NGC 4319. Our objective is to observe relative abundances and the kinematical behavior of this ion in an environment other than that of our own galaxy or the Magellanic Clouds, which have been well studied in the past. In addition to learning more about galactic coronae, our data will be useful in drawing parallels with unseen systems that produce the N V, C IV and Si IV features that appear at visible wavelengths in the spectra of high redshift quasars. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.50 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4331c PI: Edward B. Jenkins Proposal Title: HOT GAS IN THE DISK AND HALO OF NGC4319 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Edward B. Jenkins PRINCETON UNIVERSITY USA Buell T. Jannuzi INSTITUTE FOR ADVANCED STUDY USA Donald P. Schneider INSTITUTE FOR ADVANCED STUDY USA John N. Bahcall INSTITUTE FOR ADVANCED STUDY USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We will observe the Seyfert Galaxy Mrk 205 for absorption due to hot gas in either the disk or halo of NGC 4319 and our own Galaxy. The observation will be made using the GHRS with the G160M grating and the LSA, with the main objective being to cover the N V doublet that has features at 1239 and 1243 A. We will center the exposure at 1252 A, so that we can also observe 3 absorption lines of S II (1250, 1254 and 1259 A), as well as a blend of Si II and Fe II near 1260 A). This choice for a wavelength center will also allow for an adequate measurement of the continuum level below the N V doublet. Additional lines at random locations may be detected in the wavelength region we have chosen, since the Lyman-alpha forest for Mrk 205 extends from 1216 A to 1302 A. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The absorption lines which serve as diagnostics of the presence and physical conditions of the hot gas (N V, Si IV, and C IV) are not observable with ground- based telescopes. IUE can not provide the sensitivity (at high resolution) to make the necessary observations. Our previous HST observations were required in order to be able to detect the absorption due to Mg II. We plan to use the G160M grating on GHRS, with the light entering through the LSA. All of our observing will be over a single wavelength interval, but exposures will be separated into small integrations to avoid smearing due to the GIMP. The flux of Mrk 205 at 1550 A has been measured by us and another group (Bowen and Blades) using HST. An average of the two determinations is 2e-14 erg cm^-2 s^-1 A^-1. On the assumption that the band from 1235 - 1269 A has the same value, we find from an application of eq. 4-6 of the GHRS Instrument Handbook that we can expect to obtain a SNR per diode of 9.5 for a total accumulation of 7872 seconds worth of integration on the target. (A dark count rate of 0.012 counts diode^-1 s^-1 was assumed.) This SNR translates to a 1-sigma error in the equivalent width of a line that is about 20 mA, assuming N V has the same width as that measured for C IV by Bowen and Blades. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. None, except for dark time acquisition discussed in Question 6 below. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Our target Mrk 205 is faint enough to require us to perform acquisition during dark time, so that we avoid complications from the geocoronal Lyman-alpha background. The magnitudes V = 15.24 and (B - V) = 0.40 fall below the solid curve labeled N2 in Fig. 4-2 of the GHRS Instrument Handbook. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The data will be reduced at the Institute for Advanced Study using STSDAS and software developed for the reduction and analysis of the Key Project Quasar Absorption Line Survey (Schneider et al. 1992). Page 3 ------------------------------------------------------------------------------------ 8. Additional comments or special requests. No special requests. ------------------------------------------------------------------------------------ 9. Description of previous HST work. Previous programs for which Jenkins is the PI: 2344 - High Velocity Lyman Alpha Absorption in the Vela SNR 2348 - Abundance Enhancements in Halo Gas Previous programs for which Jenkins is a Co-I: 2403 - Hot Gas in the Interstellar Medium (Related) 2347 - Close Spatial Sampling of Shocked Clouds in Vela SNR 2360 - R- Process Ejecta in the Vela SNR The Co-Is' (Bahcall, Jannuzi and Schneider) prevously approve programs are the following: 1018 - Spectroscopy of a Complete Sample of Bright Nearby Quasars 1022 - Do Galaxies Produce Quasar Absorption Lines? (related) 1024 - Do Rich Clusters of Galaxies Produce Quasar Absorption Lines 2424 - Quasar Abosrption Line Sujrvey (Key Project)(Related) 2775 - Non- Proprietary (Snapshot) Survey 3463 - High Ionized Nitrogen in the Galactic Halo 3519 - UV Imaging of Nearby Galaxies (Snapshot) 3648 - Imaging of BL Lac Host Galaxies and Environments 3981 - Gravitational Lens Candidate 1208+101: Photometry 3992 - Gravitational lens Candidate 1208+101: Spectroscopy Our previous HST observations of Mrk~205 (part of GTO1022) led to the first detection of absorption (Mg II) by the intervining gas of the galaxy NGC 4319 (Bahcall \etal 1992) and were a prime motivation for the current proposal. The initial scientific results of the Key Project Quasar Absorption Line Survey (GO2424) were reported in Bahcall \etal (1992). Observations obtained during the first six months of Cycle~1 determined the number densities at small redshifts of \Lya\ systems, of C~IV lines and extragalactic halos, of Lyman-limit systems, of associated absorption systems, and of damped \Lya\ systems. The number density of C~IV absorbers at small redshifts was found to be much less than at higher redshifts. The two-point correlation function of the \Lya\ lines was computed but the number of lines in the initial sample was too small to yield a definitive result. Approximately half of the absorption lines are identified with Galactic interstellar features. The survey shows that a large fraction of the sky is covered by high or very high velocity Galactic clouds and that C~IV is present in the Galactic halo (Savage \etal 1992). ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Princeton University provides extensive computing facilities, free of any capital costs. IAS will provide computing facilities, extensive software analysis programs, an experienced computing staff, and the salaries for the Co-Is. ------------------------------------------------------------------------------------ 11. Address Information Name: Edward B. Jenkins Category: PI Institution: Princeton University Address: Princeton University Observatory City: Princeton State: NJ Zip Code: 08544 Country: USA Telephone: 609-258-3826 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4331c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 MARK205 AGN BEHIND NGC4319 RA = 12H 21M 44.1S +/- 0.1S, 2000 Z=0.070 1 V = 15.24 +/- 0.2 E,312,H,517 DEC = +75D 18' 38" +/- 1.0" 1 B-V = 0.40 1 U-B = -0.94 2 F(1500) = 2.0 +/- 0.5 E-14 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4331c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 MARK205 HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=3 1 9S 1 1 ONBOARD ACQ FOR BRIGHT=RETURN 2.000 LOCATE=YES CYCLE 3 MAP=DEF DARK TIME Comments: STEP-TIME=1S RATE COMPUTED FROM 3C273/10 = 1374 C/S ------------------------------------------------------------------------------------------------------------------------------------ 2 MARK205 HRS ACCUM 2.0 G160M 1252 STEP-PATT=5 24 328S 9 2 1 CYCLE 3 CENSOR=YES 7872S ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4331c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE=3 BRIGHT=RETURN LOCATE=YES MAP=DEF STEP-PATT=5 CENSOR=YES ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.50 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ABSORPTION LINES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2.000; CYCLE 3; DARK TIME CYCLE 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names MARK205 ------------------------------------------------------------------------------------------------------------------------------------