Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5485 Report Date: 18-Jul-95:17:31 Version: ********** Check-in Date: ********** 1.Proposal Title: LONG PERIOD VARIABLES OF M81 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GALAXIES & CLUSTERS GO 2 Long Term yrs 4348 Sub Category STELLAR POPULATIONS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Shaun M Hughes 3100 USA 818 395 4024 ------------------------------------------------------------------------------------ 7. Abstract This is part of a very long term project to identify Long-Period Variables (LPVs) in external galaxies. Most LPVs are members of the Asymptotic Giant Branch (AGB), and hence one of the main reasons for studying the LPVs will be to understand the AGB, and how it varies in nearby galaxies. So far the only AGB LPVs to be identified in external galaxies are those in the Magellanic Clouds. Ground based programs are currently underway to identify the AGB LPVs in M31 and M32, and using HST to identify the LPVs in a galaxy beyond the local group will tell us how important a part galactic environment plays in the formation of AGB progenitor stars (ie initial main sequence masses of between 0.8 and 9 solar masses). An important bonus of studying LPVs is that they possess a precise PL relation, which will be a very useful check against the distance derived from Cepheids in the H_0 key project (Program No. 2227). ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.00 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5485 PI: Shaun M Hughes Proposal Title: LONG PERIOD VARIABLES OF M81 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Shaun M Hughes 3100 USA Jeremy R Mould 3100 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. Our program aims to detect and measure accurate periods and magnitudes of Long- Period Variables (LPVs) in two M81 fields (denoted V30 and major axis). To avoid severe period aliases, we will need to obtain well-sampled light curves. The epochs of previous cycles' data have been used to search for gaps in LPV phase space, and the dates specified for cycle 4 have been carefully chosen to fill these gaps. However, as LPVs have periods of between 100 and 1000 days, we can tolerate a reasonably large scatter (+/- 10 days) about the ideal sampling times listed below. To ensure good phase coverage for the maximum number of stars it is very important for each epoch to be oriented orthogonally (ie +/- Nx90 deg) to the previous epochs' field orientations. We have obtained output from the RUN- ORIENT program to determine the allowable dates for the correct orientation for each exposure. This gives us 4 windows per year (one for each orientation), two of which last 60 days, and the other two lasting only 10 days. To obtain accurate periods, we shall need ~18 epochs in total. After the completion of cycle 3 in 1993 December, we expect to have 11 F785LP epochs (each of between 1600 and 1800 sec) of each of the two M81 fields, and therefore we shall need a further 7 epochs to complete the program. In cycle 4 we have been allocated enough time for 4 epochs (using the F814W filter, each being 300 sec). ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. So far the only AGB LPVs to be identified in external galaxies are those in the Magellanic Clouds. Ground based programs are currently underway to identify the AGB LPVs in M32, which is at the limit of current ground-based observations. Using HST to identify the LPVs in a galaxy beyond the local group will tell us how important a part galactic environment plays in the formation of AGB progenitor stars (ie initial main sequence masses of 0.8 to 9 solar masses). An important bonus of studying LPVs is that they possess a precise P-L relation, which will be a very useful check against the distance derived from Cepheids in the H_0 key project (Program No. 2227). ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. TIME CRITICAL: As described in Q3 above, the dates chosen in the EXPOSURE_LOGSHEET are such as to fill gaps in the LPV periods' phase space, while at the same time allowing orthogonal orientations to previous epochs, thereby maximising the sampling of light curves. Because the periods of LPVs are 100 to 1000 days, reasonable tolerance about these dates (+/- 10 days) is allowed. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. No calibration exposures are required. Page 3 ------------------------------------------------------------------------------------ 9. Description of previous HST work. 4348GO: Long Period Variables of M81. Hughes and Mould. 2227GO: The Extragalactic Distance Scale I. M81. H_0 team. 3905GO: The Extragalactic Distance Scale II. M81 & M101. H_0 team. 4658GO: The Extragalactic Distance Scale III. M101. H_0 team. The first program initiated the M81 LPV survey, and is for an anticipated 4 epochs in each of the two M81 fields in cycle 3 (with possibly two more epochs should the refurbishment mission be delayed). The last 3 programs are aimed at finding Cepheids in galaxies beyond the local group, and eventually out to the Virgo group. The first and nearest galaxy to be observed was M81, and in cycles 1 and 2, 18 and 6 epochs were obtained in F555W and F785LP, in two fields of M81. The F785LP frames will be used as part of the data for this LPV proposal. From the cycle 1 and 2 data, 37 Cepheid candidates have been identified. The entire data set has been calibrated against ground-based photometry (Palomar 200-inch) of the brightest stars in each of the fields. The Cepheid colors were used to estimate internal extinction, and have yielded an accurate distance to M81, the first step in measuring H_0 to better than 10%. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). A computer workstation, with associated hard disk and exabyte drive, will be used to reduce and analyse the data. ------------------------------------------------------------------------------------ 11. Address Information Name: SHAUN M HUGHES Category: PI Institution: 3100 Address: PALOMAR OBSERVATORY CALTECH, 105-24 City: PASADENA State: CA Zip Code: 91125 Country: USA Telephone: 818 395 4024 Telex (or e-mail): smh@phobos.caltech.edu ------------------------------------------------------------------------------------ Name: Category: CON Institution: Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5485 [ 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 NGC3031- E,301,B,145,175 RA=09H 51M 02.6S +/- 2", 1950 V=80 1 SURF(V)=25 +/- 1.0 FIELD DEC=+69D 23' 15" +/- 2" 2 SURF(I)=25 +/- 1.0 NGC3031- MAJOR-AXIS Comments: MAJOR-AXIS FIELD ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3031-V30 E,301,B,145,175 RA=09H 52M 03.5S +/- 2", 1950 V=80 1 SURF(V)=25 +/- 1.0 DEC=+69D 21' 18" +/- 2" 2 SURF(I)=25 +/- 1.0 Comments: V30 FIELD ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5485 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 4.1 DEFINE # WFPC2 IMAGE WFALL- F814W CR-SPLIT=NO 1 300S 10 2 # AT 21-OCT-94 +/- ICYC4 FIX 2D ORIENT -56.6D +/- 0.2D POS TARG +10, +10 Comments: THIS POSITION PUTS TARGET ON APEX AT V3PA = 123.4D (IE +0D OFF NOM) ON DAY 1994.294 (1994 OCT 21) ------------------------------------------------------------------------------------------------------------------------------------ 4.2 DEFINE # WFPC2 IMAGE WFALL- F814W CR-SPLIT=NO 1 300S 10 2 # AFTER 4.1 BY 23D + ICYC4 FIX /- 2D SAME POS FOR 4.2 AS 4.1 Comments: THIS IS ROTATED 0D WRT 4.1 AT V3PA = 123.4D (IE +18D OFF NOM) ON DAY 1994.317 (1994 NOV 13) ------------------------------------------------------------------------------------------------------------------------------------ 4.3 DEFINE # WFPC2 IMAGE WFALL- F814W CR-SPLIT=NO 1 300S 10 2 # AFTER 4.1 BY 74D + ICYC4 FIX /- 2D ORIENT -90.0D +/- 3.0D FROM 4.1 POS TARG +10, +10 Comments: THIS IS ROTATED -90D WRT 4.1 AT V3PA = 33.4D (IE -20D OFF NOM) ON DAY 1995.003 (1995 JAN 3) ------------------------------------------------------------------------------------------------------------------------------------ 4.4 DEFINE # WFPC2 IMAGE WFALL- F814W CR-SPLIT=NO 1 300S 10 2 # AFTER 4.1 BY 163D ICYC4 FIX +/- 2D ORIENT +180.0D +/- 3.0D FROM 4.1 POS TARG +10, +10 Comments: THIS IS ROTATED 180D WRT 4.1 AT V3PA = 303.4D (IE -13D OFF NOM) ON DAY 1995.092 (1995 APR 2) ------------------------------------------------------------------------------------------------------------------------------------ 40 USE NGC3031- 1 CYCLE 4 / 4.1 - ICYC4 FIELD 4.4 CYCLE 4 / 40 - 41 ------------------------------------------------------------------------------------------------------------------------------------ 41 USE NGC3031-V30 2 ICYC4 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5485 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category STELLAR POPULATIONS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AT 21-OCT-94 +/- 2D; ORIENT -56.6D +/- 0.2D; POS TARG +10, +10; AFTER 4.1 BY 23D +/- 2D; SAME POS FOR 4.2 AS 4.1; AFTER 4.1 BY 74D +/- 2D; ORIENT -90.0D +/- 3.0D FROM 4.1; AFTER 4.1 BY 163D +/- 2D; ORIENT +180.0D +/- 3.0D FROM 4.1; CYCLE 4 / 4.1 - 4.4; CYCLE 4 / 40 - 41 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC3031-FIELD NGC3031-MAJOR-AXIS NGC3031-V30 ------------------------------------------------------------------------------------------------------------------------------------