Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4392c Report Date: 09-May-96:19:35 Version: ********** Check-in Date: ********** 1.Proposal Title: ABSORPTION LINE STUDIES OF THE HIGH VELOCITY CLOUD M II - CYCLE 3 SUPPLEMENTAL ------------------------------------------------------------------------------------ 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 Dr. Laura Danly SPACE TELESCOPE SCIENCE INST USA 410-338-4422 ------------------------------------------------------------------------------------ 7. Abstract The extremely fortuitous alignment of HD 93521 and BD +38 2182 (~25 arcmin separation, z=1.5, 4.1 respectively) provides a rare opportunity to study the distribution and physical nature of gas in the milky way halo. Recent results from our IUE observations show that (1) the HVC M II is detected in absorption toward the more distant star, BD +38 2182, and (2) some evidence is found for spatial variations on scales less than 12 pc. Both of these observations have great implications for models of halo gas production. We wish to observe six setting on BD +38 2182 which, when added to the three other setting on this star that will be taken as part of our Cycle 2 program, make up a complete, complementary set of data by which to confirm and extend our studies. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 7.00 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4392c PI: Dr. Laura Danly Proposal Title: ABSORPTION LINE STUDIES OF THE HIGH VELOCITY CLOUD M II - CYCLE 3 SUPPLEMENTAL ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Dr. Laura Danly SPACE TELESCOPE SCIENCE USA INSTITUTE Mr. Kip Kuntz SPACE TELESCOPE SCIENCE USA INSTITUTE ------------------------------------------------------------------------------------ 3. Description of proposed observations. We propose to observe BD +38 2182 with three grating setting and two Echelle-B settings. The central wavelenths and species to be studied are listed after each setting. The set of observations is designed to complement the observations taken by L. Spitzer toward HD 93521 during his GTO program. \noindent BD +38 2182 (l=182.2, b=62.2, MK=B2V, V=11.2, d=4.6 kpc, z=4.1 kpc) \noindent G160M grating, SSA: \medskip $\lambda_c$=1312.0 \hskip 0.5cm t(exp)=45$^m$ \hskip 0.5cm Si I, O I, C I, Si II $\lambda_c$=1343.0 \hskip 0.5cm t(exp)=50$^m$ \hskip 0.5cm O I, C II, C II*, Cu II $\lambda_c$=1205.0 \hskip 0.5cm t(exp)=66$^m$ \hskip 0.5cm H I, C I, N I, Si II, Mn II, S III \noindent Echelle-B, SSA: \medskip $\lambda_c$=1805.0 \hskip 0.5cm t(exp)=1.4$^h$ \hskip 0.5cm S I, Si II, Ni II $\lambda_c$=2370.0 \hskip 0.5cm t(exp)=1.0$^h$ \hskip 0.5cm Fe II The first four settings toward BD +38 2182 are designed to achieve a 3$\sigma$ detection limit of 6 mA (S/N=30 for the grating settings and S/N=9 for the Echelle-B settings). Because of the good response at $\lambda$2370, we will integrate to achieve a S/N (=~25) which will give us a 3 mA detection limit. \bigskip These lines of sight will be combined with the data on BD +38 2182 that is obtained during our current Cycle 2 program (ID no. 3706). The Cycle two setups will cover the wavelength region around the high ions of C IV, Si IV, and N V. We will also get numerous other species with a range of ionization potential. In addition to studying the ionization and kinematic structure, we will have sufficient data for a detailed analysis of the depletion patterns and abundances which should prove extremely interesting, especially in the High Velocity Cloud. Page 3 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The improvement in resolution and S/N that is made available through teh GHRS on HST is required to carry out the scientific aims of the proposal. We have fully analyzed the IUE spectra which provide some tantalizing hints at what is out there, particularly with regard to the HVC detection. However, the IUE is simply not able to provide the quality of data required to make a quantitative program of halo gas measurement as envisioned here, particularly for a star of V=11.2. Of course, the ultraviolet regime is required because of the wide range of ion species available for study that are not available from the ground. \medskip Observations of HD 93521 with Copernicus are available in the literature, and provide even more useful ions, including O VI. \medskip The PI also has observed this field using the 140' single dish radio telescope at NRAO-Greenbank (with E. Albert) and using the Westerbork Interferometric Radio Telescope (with B. Wakker and H. Van Woerden). These data are being analyzed currently to provide the best information on the small scale variations in the H I distribution. The ultraviolet fluxes for the G160M grating setting observations of BD +38 2182 were measured directly from our IUE spectra of the stars. No additional corrections (i.e. for interstellar extinction) are required. The count rates (in counts/sec/diode) were determined by multiplying the fluxes by the throughputs for the GHRS/G160M and for the LSA/SSA aperture ratio given in the GHRS Instrument Handbook (Version 3.0, January 1992). \medskip We were not able to measure directly the fluxes from BD +38 2182 longward of 2000$\AA$ as we do not have any LWP spectra of this star (it's magnitude and early spectral type made it unfeasible to observe in an IUE shift). To determine the flux, we scaled from IUE spectra toward a standard B2V star, HD 32612 (LWP 7007). The count rates were determined as above for the Echelle-B throughputs, and were also scaled by the normalized blaze function given in Figure 4-14 of the Handbook. \medskip For all the grating settings, the count-rates were above the instrumental background. Exposure times were determined by t=(S/N)$^2$/(count-rate). They are listed in Section 2. For the Echelle-B settings, the inter-order scattered light had to be included in the S/N calculations. In the cases of $\lambda$1805 and $\lambda$2602, the count-rates were low enough that the instrumental background had to also be considered. The exposure times listed in Section 2 were calculated according to Equation 4-8 in the Handbook, as explained. \medskip The S/N ratios were chosen to give limiting equivalent widths that would compare reasonably with the Echelle data taken by L. Spitzer in his GTO program. In order to make a meaningful comparison, we have tried to optimize our program to create a uniform data set, given the limitation that the Echelle-A is no longer available. \newpage ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. none ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. GHRS wavelength calibrations for all spectra Page 4 ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The proposers have had extensive experience with reducing spectral data, both optical and ultraviolet. Initial reduction, and, if necessary, recalibration shall be accomplished at Space Telescope Science Institute using the STSDAS software. Detailed analysis to determine column densities, velocities, and velocity widths of the absorption line profiles will be accomplished with the existing KDAF software package (an IDL based IUE-RDAF derivative). This procedure will ensure a reduction that adheres to Space Telescope standards, yet will allow easy comparison with existing IUE and optical data. Our Cycle 2 data will have already been delivered and our data reduction and analysis procedures will by then be routine. \smallskip The data on both the high ionization species {\it and} the weakly ionized and neutral species will be analyzed in the context of models for the production of gas in the halo. Based on our work from our Cycle 2 program, we will be developing (with other collaborators R. enjamin and P. Shapiro) and refining models for predicting the non-equilibrium radiative cooling, ionization, and recombination of halo gas (for descriptions, see Shapiro, P.R. and Benjamin, R. A. 1991, Publ. A.S.P., Vol. 103, in press; Shapiro, P. R. 1991, proc. from I.A.U. Symp. No. 144 on ``The Interstellar Disk- Halo Connection in Galaxies, p 417). We wish to determine if the observed column densities {\it and} kinematics give a self-consistent picture of both the heating and flow which are predicted according to the galactic fountain. Whatever results are obtained on the physical conditions of the gas will shed light as to its origin. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. This proposal is one of several programs (including three accepted GO programs; see Question 8) designed to study gas in the environments of galaxies. These programs have been tailored specifically to meet the objectives outlined in the P.I.'s (accepted) Hubble Fellowship proposal. The goal of the Hubble Fellowship research is to study gas which is in the vicinity of a variety of galaxies, and is therefore subjected to a range of interstellar and intergalactic environments. Central to this research is a detailed study of the production and maintenance of Milky Way halo gas, where we can expect to obtain the highest quality data and develop the most detailed models. Accurate means to interpret quantitative spectroscopic data are critical to the interpretation of QSO absorption lines. \medskip Related Cycle 3 proposals includ14: \bigskip Galacti15: \smallskip $\bullet$ ``New Probes for the Intermediate Velocity Arch" (Danly, L. and Kuntz, K.D.) \medskip $\bullet$ ``The Distance of High Velocity Clouds" (Wakker, B. P., Danly, L., Schwarz, U. J., and Van Woerden, H.) \bigskip Extragalactic: \smallskip $\bullet$ ``Quasar Absorption Line Studies of Starburst Galaxy Environments" (Norman, C.N., Blades, J.C., Danly, L., and Heckman, T) \medskip $\bullet$ ``The Structure of the Coma Cluster: A Search for Cool Absorbing Gas" (Urry, C.M., Branduardi-Raymont G., Danly, L., Fitchett, M.J., Mushotzky, R.F.) \medskip $\bullet$ ``An Investigation of Strong Local Ly$\alpha$ Systems" (Urry, C. M., Bowen D., Maraschi, L., Danly, L., Bruhweiler, F. C., Falomo, R., Grady, C.) ------------------------------------------------------------------------------------ 9. Description of previous HST work. No. 3706 -- ``The Nature of Gaseous Loops in the Milky Way Halo" No. 2644 -- ``The Environments of Starburst Galaxies: Absorption Line Studies of Galactic Outflows" \bigskip The nature of both of these programs is described in Question 8. In particular, No. 3706 is closely related to the current proposed program, and is described in the Scientific Justification. No. 3706 -- one spectrum has been taken and is being analyzed. No. 2644 -- one spectrum has been taken and is being analyzed. ------------------------------------------------------------------------------------ 11. Address Information Page 5 Name: Laura Danly Category: PI Institution: Space Telescope Science Institute Address: 3700 San Martin Drive City: Baltimore State: Md Zip Code: 21218 Country: USA Telephone: 410-338-4422 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4392c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 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 BD+38D2182 G,508,509,510 PLATE-ID=01R8, J2000 V=79 1 V=11.2, TYPE=B2V, E(B-V)=0.02 GSC03009- A,110 RA= 10H 49M 12.9S +/- 0.1S, 2 B-V=-0.22 02485 DEC= +38D 0' 14.5" +/- 1" 3 F-CONT(1240) = 36 E-13 4 F-CONT(1300) = 24 E-13 5 F-CONT(1400) = 22 E-13 6 F-CONT(1800) = 12 E-13 7 F-CONT(2400) = 7 E-13 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4392c [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 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 BD+38D2182 HRS ACQ 2.0 MIRROR-A2 BRIGHT=RETURN 1 3.6S 1 1 CYCLE 3/ 1.0 - 5.2 ONBOARD ACQ FOR 1.10 - 5.20 Comments: STEP-TIME = 0.4 ------------------------------------------------------------------------------------------------------------------------------------ 1.1 WAVE HRS ACCUM SC2 G160M 1312 1 DEF 1 CALIB FOR 1.2 SEQ 1.1-1.2 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 1.2 BD+38D2182 HRS ACCUM 0.25 G160M 1312 FP-SPLIT=STD 1 40M 28 4 1 ------------------------------------------------------------------------------------------------------------------------------------ 2.1 WAVE HRS ACCUM SC2 G160M 1343 1 DEF 1 CALIB FOR 2.2 SEQ 2.1-2.2 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 2.2 BD+38D2182 HRS ACCUM 0.25 G160M 1343 FP-SPLIT=STD 2 25M 28 4 1 ------------------------------------------------------------------------------------------------------------------------------------ 3.1 WAVE HRS ACCUM SC2 G160M 1205 1 DEF 1 CALIB FOR 3.2 SEQ 3.1-3.2 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 3.2 BD+38D2182 HRS ACCUM 0.25 G160M 1205 FP-SPLIT=STD 2 30M 30 3 1 ------------------------------------------------------------------------------------------------------------------------------------ 4.1 WAVE HRS ACCUM SC2 ECH-B 1805 STEP-PATT=8 1 DEF 1 CALIB FOR 4.2 SEQ 4.1-4.2 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 4.2 BD+38D2182 HRS ACCUM 0.25 ECH-B 1805 FP-SPLIT=STD 3 30M 9 4 1 STEP-PATT=8 CENSOR=YES ------------------------------------------------------------------------------------------------------------------------------------ 5.1 WAVE HRS ACCUM SC2 ECH-B 2370 STEP-PATT=6 1 DEF 1 CALIB FOR 5.2 SEQ 5.1-5.2 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 5.2 BD+38D2182 HRS ACCUM 0.25 ECH-B 2370 FP-SPLIT=STD 2 30M 25 7 1 STEP-PATT=6 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4392c [ 8] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN FP-SPLIT=STD STEP-PATT=8 CENSOR=YES STEP-PATT=6 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 7.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ABSORPTION LINES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 3/ 1.0 - 5.2; ONBOARD ACQ FOR 1.10 - 5.20 CALIB FOR 1.2; SEQ 1.1-1.2 NO GAP CALIB FOR 2.2; SEQ 2.1-2.2 NO GAP CALIB FOR 3.2; SEQ 3.1-3.2 NO GAP CALIB FOR 4.2; SEQ 4.1-4.2 NO GAP CALIB FOR 5.2; SEQ 5.1-5.2 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-A2 G160M ECH-B ------------------------------------------------------------------------------------------------------------------------------------ Target Names BD+38D2182 GSC03009-02485 ------------------------------------------------------------------------------------------------------------------------------------