! File: 2230C.PROP ! Database: PEPDB ! Date: 17-FEB-1994:03:42:13 coverpage: title_1: DISTANCE TO THE SEYFERT GALAXY NGC 4151 DETERMINED BY title_2: PARALLEL OBSERVATIONS WITH THE WFC sci_cat: GALAXIES & CLUSTERS sci_subcat: DISTANCE SCALE proposal_for: GO pi_title: DR. pi_fname: AINA pi_lname: ELVIUS pi_inst: STOCKHOLM OBSERVATORY pi_country: SWEDEN pi_phone: +46 8 7170380 keywords_1: SEYFERT GALAXY, DISTANCE DETERMINATION, keywords_2: GLOBULAR CLUSTERS hours_par: 10.00 num_par: 4 wf_pc: Y pi_position: PROFESSOR off_fname: GOSTA off_lname: GAHM off_title: DIRECTOR off_inst: STOCKHOLM OBSERVATORY off_addr_1: S-133 36 SATLSJOEBADEN off_country: SWEDEN off_phone: +46 8 7170380 ! end of coverpage abstract: line_1: The nearest Seyfert 1 galaxy NGC 4151 has a rapidly variable line_2: nucleus with interesting features. It has been studied extensively line_3: by the proposers with IUE and ground-based telescopes. Parameters line_4: which we want to derive from the observations, like the dimensions line_5: of an accretion disk around a possible black hole and the amount line_6: of energy emitted from the active nucleus, depend on the distance line_7: to NGC 4151. Therefore it is essential to determine the distance line_8: as accurately as possible. Distance estimates based on the redshift line_9: (presently 10 to 20 Mpc) are not good enough because of a possible line_10: peculiar motion of the same order as the Hubble flow. line_11: We propose to use the WFC for exposures of the outer spiral line_12: structure and surroundings of NGC 4151 in parallel with observations line_13: of the nucleus with another instrument. We intend to search the line_14: fields for distance indicators such as globular clusters, HII line_15: regions, supergiant stars and Cephied variables and to determine line_16: their magnitudes and approximate colours. The distance indicators line_17: are too faint to be observed from the ground but should be line_18: comfortably measured with the HST. ! ! end of abstract general_form_proposers: lname: ELVIUS fname: AINA title: DR. inst: STOCKHOLM OBSERVATORY country: SWEDEN esa: Y ! lname: ALTAMORE fname: A. title: DR. inst: INSTITUTO ASTRONOMICO DELL'UNIVERSITA, ROME country: ITALY esa: Y ! lname: BOKSENBERG fname: ALEC title: PROF. inst: ROYAL GREENWICH OBSERVATORY, HAILSHAM country: UK esa: Y ! lname: BROMAGE fname: GORDON title: DR. mi: E inst: RUTHERFORD AND APPLETON LABORATORY, CHILTON country: UK esa: Y ! lname: CLAVEL fname: JEAN title: DR. inst: ESA IUE OBSERVATORY, MADRID country: SPAIN esa: Y ! lname: FOSBURY fname: ROBERT title: DR. mi: A inst: ST-ECF country: FRG esa: Y ! lname: PEROLA fname: G. title: PROF. mi: C inst: INSTITUTO ASTRONOMICO DELL'UNIVERSITA, ROME country: ITALY esa: Y ! lname: PENSTON fname: MICHAEL title: DR. mi: V inst: ROYAL GREENWICH OBSERVATORY, CAMBRIDGE country: UK esa: Y ! lname: SNIJDERS fname: M. title: DR. mi: A inst: ASTRONOMISCHES INSTITUT TUEBINGEN country: FRG esa: Y ! lname: ULRICH fname: MARIE-HELENE title: DR. inst: EUROPEAN SOUTHERN OBSERVATORY country: FRG esa: Y ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: We propose parallel observations with the WFC when central line_2: regions of NGC 4151 are observed with one of the axial SIs. We will line_3: use the WFC in a serendipitous mode to search for objects of interest line_4: especially suitable distance indicators such as globular clusters, line_5: HII regions, luminous stars and Cephied variables. line_6: The field covered by the WFC in parallel mode will depend on the line_7: instrument used in the primary mode and on the roll angle of the HST. line_8: We have identified three main cases: line_9: 1. NGC 4151 nucleus in the FOS will permit WFC observations of spiral line_10: arms and we expect to find all types of distance indicators line_11: mentioned above. The filter F439W will be used to study HII line_12: regions and, with F702W, will also be used for colours line_13: of other objects for which F555W will be used for V line_14: magnitudes. line_15: 2.NGC 4151 nucleus in GHRS and an HST roll angle of 175 +/- 15 deg line_16: places NGC4156 into the WFC FOV. We propose the same filters as line_17: in case 1 but somewhat longer exposures. line_18: 3.(If and when FOC/WFPC parallel observations are allowed). NGC 4151 line_19: in FOC or in HRS with other roll angles than in case 2 will give line_20: WFC fields outside the main structure of the galaxy, making line_21: globular clusters the main targets. Filters F555W and F702W line_22: are proposed for V magnitudes and colours. line_23: In all cases it is essential for the colour measures that the ! question: 3 section: 2 line_1: same region be observed with different filters. If it is sometimes line_2: possible to make only one exposure of a certain region, the filter line_3: F439W is preferred in cases 1 and 2 for studies of HII regions and line_4: the filter F555W in case 3 for the identification of non-stellar line_5: objects such as globular clusters and for measures of V magnitudes. line_6: Observations well outside the main spiral arms are of importance line_7: also for statistical studies of foreground Galactic stars which must line_8: be considered when stellar objects in the spiral arms of NGC 4151 line_9: are studied. Also, in the search for globular clusters, such studies line_10: will be of some help. ! question: 4 section: 1 line_1: These distance indicators are too faint to be observed from the line_2: ground. In order to identify the globular clusters as non-stellar line_3: objects and to determine their luminosity function down to about line_4: Mv=-5, we need to reach V=27 at the distance of NGC 4151. Possible line_5: Cephied variables should be identified to the same magnitude. line_6: The deepest pictures of NGC 4151 so far seem to be those line_7: published by Arp (1977). He used some of the largest ground-based line_8: telescopes and special copying techniques to produce prints line_9: reaching down to magnitude 25 (his estimate). The published prints line_10: have been used by us for determining suitable WFC fields as line_11: mentioned above. This material cannot be used for precise distance line_12: determination. line_13: Arp has used photographs in red light of the inner structures line_14: of NGC 4151 to measure the diameters of some HII regions there. line_15: We should like to measure HII regions in the spiral arms, expecting line_16: that they will be more representative of the standards used in line_17: distance determinations and that their diameters can be measured line_18: more precisely with the HST. ! question: 5 section: 1 line_1: We need to measure at least 25 to 30 globular clusters in order line_2: to use a proposed statistical method. As we do not know beforehand line_3: where to find these or other distance indicators, we plan for line_4: observations of about 6 regions with the WFC in parallel mode, the line_5: regions in each of the 3 cases detailed in section 3 above and using line_6: 2 or 3 filters for each region we arrive at about 14 exposures. line_7: Exposure times will range from 1800 s to 3000 s with most at about line_8: 2500 s. line_9: As shown in the computer simulations made so far, the 2500 s line_10: exposure is expected to show very clearly a globular cluster as line_11: a non-stellar object when an integrated absolute magnoiude of -7.4 line_12: and a distance of 15Mpc are assumed. We want to reach also clusters line_13: about 2 magnitudes fainter. The distance may be more or less than line_14: 15Mpc. ! question: 7 section: 1 line_1: We plan to make copies of the HST data as they become available line_2: so that each institution in our group has a data set. Each of line_3: us has access to a VAX computer or SUN workstation on which will line_4: be implemented reduction and analysis s/w from STScI and ST-ECF. line_5: We are a large group and are used to working together. line_6: The CCD frames will be searched for various kinds of objects line_7: mentioned in this proposal. As necessary, computer simulations line_8: of non-stellar objects will be made for comparison. line_9: Magnitudes and colours of identified distance indicators will line_10: be determined in the instrumental system and either directly used line_11: for distance determination using other HST data obtained in line_12: similar programmes or calibrated in terms of standard systems line_13: (like U, B, V) by means of calibrations in the HST archive, so line_14: that the HST data can be compared with ground-based studies. ! question: 9 section: 1 line_1: A line_2: A. Boksenberg line_3: GTO program 1222 FOC not closely relevant line_4: 1216-1220, 1223, 1225-1227, 1240 not relevant but same line_5: subject area line_6: 1245, 1261 not relevant ! question: 10 section: 1 line_1: Our institutions will provide adequate computing time for line_2: reducing the data. The most recent data reduction and analysis s/w line_3: will be implemented and continuously updated in our different line_4: institutions. ! !end of general form text general_form_address: lname: ELVIUS fname: AINA title: DR category: PI inst: STOCKHOLM OBSERVATORY addr_1: S-133 36 SALTSJOEBADEN country: SWEDEN phone: +46 8 7170380 telex: 12972 SOBSERV S ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: NGC4151-NUCLEUS name_2: GSC3017-939 descr_1: GALAXY, AGN, descr_2: SEYFERT GALAXY pos_1: PLATE-ID=01QY, pos_2: RA=12H 10M 32.518S +/- 0.2", pos_3: DEC=+39D 24' 20.77" +/- 0.2" equinox: 2000 pos_epoch_bj: J pos_epoch_yr: 1984.00 rv_or_z: Z=0.0032 comment_1: SEYFERT NUCLEUS OBSERVED ONLY IN comment_2: PRIMARY MODE WITH OTHER SI. comment_3: THE FOLLOWING LINE NUMBERS ARE FOR comment_4: PARALLEL MODE OBSERVATIONS WITH comment_5: WFC AND SO THIS TARGET IS NOT comment_6: REFERENCED IN THE EXPOSURE LOGSHEET comment_7: FOR THIS PROPOSAL. fluxnum_1: 1 fluxval_1: V=13 ! targnum: 2 name_1: NGC4151-POS1 descr_1: EXT-CLUSTER; descr_2: EXT-MEDIUM; descr_3: EXT-STAR comment_1: ANY REGION OBSERVED IN PARALLEL comment_2: WITH NGC4151 NUCLEUS IN A FOS APER. fluxnum_1: 2 fluxval_1: V = 24 +/- 3 ! targnum: 3 name_1: NGC4151-POS2 descr_1: EXT-CLUSTER; descr_2: EXT-MEDIUM; descr_3: EXT-STAR comment_1: ANY REGION OBSERVED IN PARALLEL comment_2: WITH NGC4151 NUCLEUS INCLUDING ALL comment_3: OR PART OF NGC 4156 (=GSC3017-663, comment_4: CZ=6700KM/S). comment_5: EG. GHRS WITH ROLL=175 +/- 15 DEG comment_6: OR FOC WITH ROLL CLOSE TO 0 DEG. fluxnum_1: 2 fluxval_1: V = 24 +/- 3 ! targnum: 4 name_1: NGC4151-POS3 descr_1: EXT-CLUSTER; descr_2: GLOBULAR CLUSTER comment_1: ANY REGION OBSERVED IN PARALLEL comment_2: WITH NGC4151 NUCLEUS IN GHRS APER. comment_3: PROPOSAL 2469 USING GHRS HAS comment_4: ASKED FOR STEP-TIME=1.0 comment_5: TO ENABLE WFC PAR. OBS. fluxnum_1: 2 fluxval_1: V = 24 +/- 3 ! targnum: 5 name_1: NGC4151-POS4 descr_1: EXT-CLUSTER; descr_2: GLOBULAR CLUSTER comment_1: ANY REGION OBSERVED IN PARALLEL comment_2: WITH NGC4151 NUCLEUS IN A FOC APER. comment_3: (IF AND WHEN THIS OPTION comment_4: BECOMES AVAILABLE.) fluxnum_1: 2 fluxval_1: V = 24 +/- 3 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: CASE-1 targname: NGC4151-POS1 config: WFC opmode: IMAGE aperture: ANY sp_element: F555W num_exp: 1 time_per_exp: 40M s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: PAR ! linenum: 2.000 sequence_1: ^ targname: NGC4151-POS1 config: WFC opmode: IMAGE aperture: ANY sp_element: F439W num_exp: 1 time_per_exp: 45M s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: PAR; req_2: SAME POS FOR 2 AS 1 comment_1: SLIGHT POSITION DIFFERENCES comment_2: ARE ACCEPTABLE - AS LONG AS comment_3: MOST OF THE FIELD IS IN COMMON. ! linenum: 3.000 sequence_1: ^ targname: NGC4151-POS1 config: WFC opmode: IMAGE aperture: ANY sp_element: F702W num_exp: 1 time_per_exp: 40M s_to_n: 10 fluxnum_1: 2 priority: 2 req_1: PAR; req_2: SAME POS FOR 3 AS 1 comment_1: SLIGHT POSITION DIFFERENCES comment_2: ARE ACCEPTABLE - AS LONG AS comment_3: MOST OF THE FIELD IS IN COMMON. ! linenum: 4.000 sequence_1: DEFINE sequence_2: CASE-2 targname: NGC4151-POS2 config: WFC opmode: IMAGE aperture: ANY sp_element: F555W num_exp: 1 time_per_exp: 45M s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: PAR ! linenum: 5.000 sequence_1: ^ targname: NGC4151-POS2 config: WFC opmode: IMAGE aperture: ANY sp_element: F439W num_exp: 1 time_per_exp: 45M s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: PAR; req_2: SAME POS FOR 5 AS 4 comment_1: SLIGHT POSITION DIFFERENCES comment_2: ARE ACCEPTABLE - AS LONG AS comment_3: MOST OF THE FIELD IS IN COMMON. ! linenum: 6.000 sequence_1: ^ targname: NGC4151-POS2 config: WFC opmode: IMAGE aperture: ANY sp_element: F702W num_exp: 1 time_per_exp: 45M s_to_n: 10 fluxnum_1: 2 priority: 2 req_1: PAR; req_2: SAME POS FOR 6 AS 4 comment_1: SLIGHT POSITION DIFFERENCES comment_2: ARE ACCEPTABLE - AS LONG AS comment_3: MOST OF THE FIELD IS IN COMMON. ! linenum: 7.000 sequence_1: DEFINE sequence_2: CASE-3 targname: NGC4151-POS3 config: WFC opmode: IMAGE aperture: ANY sp_element: F555W num_exp: 1 time_per_exp: 45M s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: PAR ! linenum: 8.000 sequence_1: ^ targname: NGC4151-POS3 config: WFC opmode: IMAGE aperture: ANY sp_element: F702W num_exp: 1 time_per_exp: 45M s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: PAR; req_2: SAME POS FOR 8 AS 7 comment_1: SLIGHT POSITION DIFFERENCES comment_2: ARE ACCEPTABLE - AS LONG AS comment_3: MOST OF THE FIELD IS IN COMMON. ! linenum: 9.000 sequence_1: DEFINE sequence_2: CASE-4 targname: NGC4151-POS4 config: WFC opmode: IMAGE aperture: ANY sp_element: F555W num_exp: 1 time_per_exp: 45M s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: PAR ! linenum: 10.000 sequence_1: DEFINE sequence_2: CASE-4 targname: NGC4151-POS4 config: WFC opmode: IMAGE aperture: ANY sp_element: F702W num_exp: 1 time_per_exp: 45M s_to_n: 10 fluxnum_1: 2 priority: 1 req_1: PAR; req_2: SAME POS FOR 10 AS 9 comment_1: SLIGHT POSITION DIFFERENCES comment_2: ARE ACCEPTABLE - AS LONG AS comment_3: MOST OF THE FIELD IS IN COMMON. ! linenum: 11.000 sequence_1: USE sequence_2: CASE-1 comment_1: WHENEVER PARALLEL OPPORTUNITY comment_2: ARISES. ! linenum: 12.000 sequence_1: USE sequence_2: CASE-2 comment_1: WHENEVER PARALLEL OPPORTUNITY comment_2: ARISES. ! linenum: 13.000 sequence_1: USE sequence_2: CASE-3 comment_1: WHENEVER PARALLEL OPPORTUNITY comment_2: ARISES. ! linenum: 14.000 sequence_1: USE sequence_2: CASE-4 comment_1: WHENEVER PARALLEL OPPORTUNITY comment_2: ARISES. ! ! end of exposure logsheet ! No scan data records found