As discussed previously with Dr. Tony Roman it was necessary to make some minor modifications to the observing strategy: instead of one long strip of 5 adjacent positions, we have now concentated on the two most important areas and increased the areal coverage for one of them. IMPORTANT: I noticed that visit 1 is now 6 orbits. There is no scientific reason but a practical one: the complex mapping/dither pattern in three filters would have taken significantly more time if I had split it by filter. I could not split the map and maintain symmetry. However, I am a first-time APT user and may have overlooked a good solution. If 6 orbits create a scheduling problem I'm happy to modify phase-II with a better implementation plan. ----- Attempting Submission 1 (Fri May 18 22:41:17 GMT 2007) ----- Assigned ID: 501 ----- Attempting Submission 1 (Fri Jan 26 22:35:02 GMT 2007) ----- The IMF in the Hidden Galactic Starburst W49A W49A is one of the most luminous and prolific massive star formation regions in the disk of our Milky Way. Given the presence of several very massive OB clusters as well as an unusually high concentration of many young ultra-compact HII regions (UCHIIR) -- all embedded in about 1 million solar masses of molecular gas -- it is arguably the best Galactic template for a luminous starburst region. We propose to obtain NICMOS imaging of the central part of W49A, covering a strip from the central, massive OB cluster to the ring of UCHIIRs. Our goals are to resolve and characterize the central star cluster and determine its IMF down to about 1 solar mass. We want to characterize the distribution of intermediate-mass YSOs, and identify the NIR counterparts to the UCHIIRs. The combination of the proposed HST/NICMOS data with our recently obtained Spitzer observations would allow a great step forward in the understanding of massive star and cluster formation.
Our strategy is to image a representative strip of five adjacent positions across the central part of W49A with NIC2 in the F110W, F160W, and F205W filters. The most important, known locations are the central OB cluster at 19:10:17.52, +09:06:22.1 (J2000), and the Welch ring of UCHIIR at 19:10:13.40, +09:06:12.8 (J2000). The five adjacent pointings, will include those two locations. observing sequence: Orbit 1: Guide star acquisition: 360s, Instrument setup (F110W): 18s, Position 1: 2700s Orbit 2: Instrument setup (F110W): 18s, Position 1: 3100s Orbit 3: Instrument setup (F160W): 18s, Position 1: 700s, Instrument setup (F205W): 18s, Position 1: 1280s, SAM to position 2: 40s, Position 2 ? part 1: 1000s Orbit 4: Instrument setup (F205W): 18s, Position 2 ? part 2: 280s, Instrument setup (F160W): 18s, Position 2: 700s, Instrument setup (F110W): 18s, Position 2: 1280s, SAM to position 3: 40s, Position 3 ? part 1: 700s Orbits 5-7: continue in the way of orbits 3 and 4 until all five positions have been observed. Orbit 8: Guide star acquisition: 360s, Instrument setup (F110W): 18s, Control Field position: 2700s Orbit 9: Instrument setup (F110W): 18s, Control field position: 1000s, Instrument setup (F160W): 18s, Control field position: 700s, Instrument setup (F205W): 18s, Control field position: 1280s. The total time requested for object and control field adds up to 9 orbits. STAR FORMATION 12 false 0.0 false false false false false false SUPPORTED STELLAR CLUSTER OB ASSOCIATION STAR FORMING REGION SHOCK FRONT YOUNG ASSOCIATION EMISSION LINE NEBULA J2000 19 10 17.5200 +09 06 22.10 J2000 STELLAR CLUSTER HALO OPEN CLUSTER STAR FORMING REGION J2000 00 00 0.0000 +00 00 0.00 J2000 STELLAR CLUSTER STAR FORMING REGION SHOCK FRONT YOUNG ASSOCIATION EMISSION LINE NEBULA OB ASSOCIATION J2000 19 10 17.5200 +09 06 22.10 J2000 NIC2 Imaging No No F110W NIC2 Imaging No No F160W NIC2 Imaging No No F205W NIC2 Imaging No No F110W NIC2 Imaging No No F160W NIC2 Imaging No No F205W CELESTIAL MOSAIC DITHER 4 9 The idea is to use a 3 by 3 mapping pattern of 9" offsets to enlarge the observed area to 37" by 37" while providing increased resolution and 4-fold redundancy via dithering in each of the mapping positions. NIC-SPIRAL-DITH true true 1.125 9 0 POS-TARG NIC-SPIRAL-MAP 0 1 true POS-TARG DITHER DITHER 1.125 Simple dither pattern to increase resolution and redundancy NIC-XSTRIP-DITH false true 9 0 POS-TARG NIC-SPIRAL-DITH 0 2 false /disks/sirtf1/PROPOSALS/W49A/OP-cache/NICMOS_phaseII-v01.xml Central OB cluster in F110W, F165M, F207M (Tic-Visit :proposal-id 11168 :visit-id "01" :proposal-version -1 :trans-version "20070325" :date "19-May-2007 00:16:41.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 6 :saa-model "23" :si-bright-earth-limb-angle 20.0 :data-volume 4054848 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11168 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11168 :visit-id "01" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2707 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11168 :visit-id "01" :orbit-number 2 :pcs-time 355 :si-vis-utilization 2716 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11168 :visit-id "01" :orbit-number 3 :pcs-time 355 :si-vis-utilization 2705 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11168 :visit-id "01" :orbit-number 4 :pcs-time 355 :si-vis-utilization 2716 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11168 :visit-id "01" :orbit-number 5 :pcs-time 355 :si-vis-utilization 2705 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11168 :visit-id "01" :orbit-number 6 :pcs-time 355 :si-vis-utilization 2685 :al-overhead-at-end 0 :internal-dur-at-end 116 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) true 6 0 /disks/sirtf1/PROPOSALS/W49A/OP-cache/NICMOS_phaseII-v01.xml /disks/sirtf1/PROPOSALS/W49A/OP-cache/NICMOS_phaseII-v02.xml UCHIIR Welch ring and control field in F110W, F165M and F207M (Tic-Visit :proposal-id 11168 :visit-id "02" :proposal-version -1 :trans-version "20070325" :date "19-May-2007 00:19:25.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "23" :si-bright-earth-limb-angle 20.0 :data-volume 1669632 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11168 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 11168 :visit-id "02" :obset-id "A2" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11168 :visit-id "02" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2662 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11168 :visit-id "02" :orbit-number 2 :pcs-time 355 :si-vis-utilization 2775 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11168 :visit-id "02" :orbit-number 3 :pcs-time 355 :si-vis-utilization 2069 :al-overhead-at-end 0 :internal-dur-at-end 116 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) true 3 0 /tmp/OPVisit51353.xml