updated phase II taking into account changes in observing strategy following the SM4 mission.----- Attempting Submission 1 (Thu Jul 03 09:26:51 GMT 2008) -----
----- Attempting Submission 2 (Mon Jun 15 10:33:12 GMT 2009) -----Assigned ID: 326
----- Attempting Submission 1 (Fri Mar 07 12:39:11 GMT 2008) -----
Phase I Proposal 326 (phaseI.apt) successfully submitted.Super star clusters in the starburst core of M82M82 is the archetype starburst galaxy and the nearest (3.6 Mpc) analogue to the star-forming galaxies identified at high-z. No other galaxy affords the opportunity to study an active starburst at such high spatial resolution, and with such a wealth of complimentary data available in the literature. In our cycle 10 STIS programme, we carried out the first spectroscopic study of a cluster in the core of the M82 starburst. Intriguingly, we found this young (6.5 Myr) cluster to be surrounded by a compact (4.5 pc), high-pressure HII region, whose evolution appears to have been significantly affected by the high ambient pressures found in this region of the starburst. We therefore propose to obtain spatially resolved STIS spectroscopy of a sample of star clusters within the starburst core, distributed over a range of ambient conditions. Together with measuring accurate ages, masses, sizes, and extinctions of the star clusters, we will also measure the properties of their immediate environments (gas dynamics, pressures/densities, excitations). Only with the spatial resolution of STIS can we isolate individual clusters in the crowded starburst core of M82, where the background is also bright and highly variable.
The data from this proposal will uniquely chart relationships between SSCs and the ISM in their immediate vicinities. By so doing, they will provide the first systematic measurements of how SSCs transmit their power to their surroundings, and ultimately to the starburst-powered galactic wind.M82 is the nearest giant starburst where multiple SSCs are optically accessible within the starburst zone, and is therefore the most important laboratory we possess for examining intense star formation. We plan to use STIS to observe a sample of SSCs and their immediate environments in the core of the M82 starburst, thereby increasing the number of core star clusters with spectroscopic observations by a factor of 2-3. For these clusters we have accurate astrometry derived from HST ACS imaging and ground-based data, and B-band (F435W) magnitudes and visual extinctions from Mayya et al. (2008). Magnitudes of our selected clusters range between B=18.4-19.7 mag. The 52"x0.1" slit gives a resolution, perpendicular to the dispersion direction, of 1.8 pc at the distance of M82 and takes nearly full advantage of HST's spatial resolution.
We will orient the spectrograph slit to cover 3-4 individual clusters in the brightest starburst clump (clump A) with one pointing. Regardless of the individual clusters themselves, positioning the slit across clump A is a major advantage in understanding how the inter-cluster medium is evolving in this unique environment. Here there are many densely packed clusters and a high X-ray brightness, and we believe this clump to be base of the current wind (Westmoquette et al. 2007).
Two grating settings will be used: G430L to cover the blue spectral region from 2900-5700 Angstroms (primarily absorption lines and the Balmer jump), and G750M centred at 6768 Angstroms to cover the H-alpha, [NII], and [SII] emission line region. The 0.1" slit yields a spectral resolution of 2.5 pixels (or 6.7 Angstroms in the G430L grating and 1.4~ Angstroms in the G750M grating), which is necessary both to perform accurate spectral synthesis on the spectra, and to isolate the targeted clusters within the crowded field.
For exposure time estimates, we used the following STIS ETC settings: we assume an extended source of 0.3" radius and take B-band magnitudes measured from Mayya et al. (2008; measured using aperture photometry on the ACS F435W image), together with an B0V template spectrum (representing the expected dominant stellar type in the core region). We adopt a characteristic visual extinction (A_V) of 5 mag for the whole of the starburst core (Westmoquette et al. 2007). Our S/N requirements are driven by our previous experience with similar STIS observations, with spectral synthesis techniques and with being able to accurately measure the line profile shapes: we require a mean S/N of ~30-40 per spectral resolution element in the 3800-4800 Angstroms range and ~10 in the red. Thus, we find that for the G430L spectrum, we will require 43000 sec (12 orbits), and 14000 sec (4 orbits) for the G750M spectrum. This is consistent with our previous experience. Including overheads, our total request comes to 16 orbits, of which we have been allocated all 16. These will be split into 4 visits of 4 orbits each.
Since the cluster we wish to centre the slit on is very near (~1.5") to the bright cluster A1, we will initially centre on cluster A1 then offset to our target cluster.
Because of our ORIENT requirements, we cannot (according to Sect 4.1 of the Call for Proposals) take advantage of the fact that M82 lies in the Continuous Viewing Zone (CVZ).UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE12false0.00.0falsefalsefalsefalsefalseSUPPORTEDEXT-CLUSTEREMISSION LINE NEBULASTAR FORMING REGIONYOUNG ASSOCIATIONThis is the target star cluster (cluster A2)
To centre on it, we need to offset from cluster A1 - the brightest source.B=19.66 mag, E(B-V)~1.3509 55 53.2900+69 40 48.43J2000EXT-CLUSTEREMISSION LINE NEBULASTAR FORMING REGIONYOUNG ASSOCIATIONCluster A1: to acquire then offset to cluster A2J200000 00 0.0000+00 00 0.00J2000STIS/CCDSpectroscopicNoNoG430L4300STIS/CCDSpectroscopicNoNoG750M6768POS-TARGDITHER0.4153 dithers along the slit (by integer pixel shifts), to help with removal of hot and cold pixelsLINEfalsetrue390.0STIS-ALONG-SLIT1falsePOS-TARGDITHER0.4154 dithers along the slit (by integer pixel shifts), to help with removal of hot and cold pixelsLINEfalsetrue490.0STIS-ALONG-SLIT2falseSame orient constraint links visits (01 02 03 04)The scheduling data was generated by CASM 17.2.CASM was run in Phase II mode./private/tmp/OPVisit35070.xmlG430L visit 1
1. Acquire brightest target in region (M82 A1)
2. Offset to cluster A2 and peak up
3. science exposure following a 3-point dither along the length of the slit - END ORBIT 1
4. peak up and science sequence for each following orbit(Tic-Visit
:proposal-id 11641
:visit-id "01"
:proposal-version -1
:trans-version "20090130"
:date "15-Jun-2009 11:26:34.0"
:trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0
:FATAL-ERRORS 0 :CONTINUABLE-FATALS 0)
:number-of-orbits 4
:saa-model "24"
:si-bright-earth-limb-angle 20.0
:data-volume 368576
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 11641
:visit-id "01"
:obset-id "01"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 11641
:visit-id "01"
:orbit-number 1
:pcs-time 333
:si-vis-utilization 3281
: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 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "01"
:orbit-number 2
:pcs-time 195
:si-vis-utilization 3412
:al-overhead-at-end 75
:internal-dur-at-end 0
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "01"
:orbit-number 3
:pcs-time 195
:si-vis-utilization 3412
:al-overhead-at-end 72
:internal-dur-at-end 0
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "01"
:orbit-number 4
:pcs-time 195
:si-vis-utilization 3415
:al-overhead-at-end 0
:internal-dur-at-end 362
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)true40point source acquisition using the long-pass filterPeakUp with the 52x0.1E1 mask and the mirrorPeakUp with the 52x0.1E1 mask and the mirrorSame orient constraint links visits (01 02 03 04)The scheduling data was generated by CASM 17.2.CASM was run in Phase II mode./private/tmp/OPVisit35069.xmlG430L visit 2(Tic-Visit
:proposal-id 11641
:visit-id "02"
:proposal-version -1
:trans-version "20090130"
:date "15-Jun-2009 11:25:50.0"
:trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0
:FATAL-ERRORS 0 :CONTINUABLE-FATALS 0)
:number-of-orbits 4
:saa-model "24"
:si-bright-earth-limb-angle 20.0
:data-volume 368576
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 11641
:visit-id "02"
:obset-id "02"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 11641
:visit-id "02"
:orbit-number 1
:pcs-time 333
:si-vis-utilization 3281
: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 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "02"
:orbit-number 2
:pcs-time 195
:si-vis-utilization 3412
:al-overhead-at-end 75
:internal-dur-at-end 0
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "02"
:orbit-number 3
:pcs-time 195
:si-vis-utilization 3412
:al-overhead-at-end 72
:internal-dur-at-end 0
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "02"
:orbit-number 4
:pcs-time 195
:si-vis-utilization 3415
:al-overhead-at-end 0
:internal-dur-at-end 362
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)true40point source acquisition using the long-pass filterPeakUp with the 52x0.1 mask and the mirrorPeakUp with the 52x0.1 mask and the mirrorSame orient constraint links visits (01 02 03 04)The scheduling data was generated by CASM 17.2.CASM was run in Phase II mode./private/tmp/OPVisit35068.xmlG430L visit 3(Tic-Visit
:proposal-id 11641
:visit-id "03"
:proposal-version -1
:trans-version "20090130"
:date "15-Jun-2009 11:25:43.0"
:trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0
:FATAL-ERRORS 0 :CONTINUABLE-FATALS 0)
:number-of-orbits 4
:saa-model "24"
:si-bright-earth-limb-angle 20.0
:data-volume 368576
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 11641
:visit-id "03"
:obset-id "03"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 11641
:visit-id "03"
:orbit-number 1
:pcs-time 333
:si-vis-utilization 3281
: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 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "03"
:orbit-number 2
:pcs-time 195
:si-vis-utilization 3412
:al-overhead-at-end 75
:internal-dur-at-end 0
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "03"
:orbit-number 3
:pcs-time 195
:si-vis-utilization 3412
:al-overhead-at-end 72
:internal-dur-at-end 0
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "03"
:orbit-number 4
:pcs-time 195
:si-vis-utilization 3415
:al-overhead-at-end 0
:internal-dur-at-end 362
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)true40point source acquisition using the long-pass filterPeakUp with the 52x0.1 mask and the mirrorPeakUp with the 52x0.1 mask and the mirrorSame orient constraint links visits (01 02 03 04)The scheduling data was generated by CASM 17.2.CASM was run in Phase II mode./private/tmp/OPVisit35072.xmlG750M setting, 4 orbits(Tic-Visit
:proposal-id 11641
:visit-id "04"
:proposal-version -1
:trans-version "20090130"
:date "15-Jun-2009 11:32:39.0"
:trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0
:FATAL-ERRORS 0 :CONTINUABLE-FATALS 0)
:number-of-orbits 4
:saa-model "24"
:si-bright-earth-limb-angle 20.0
:data-volume 368576
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 11641
:visit-id "04"
:obset-id "04"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 11641
:visit-id "04"
:orbit-number 1
:pcs-time 333
:si-vis-utilization 3276
: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 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "04"
:orbit-number 2
:pcs-time 195
:si-vis-utilization 3412
:al-overhead-at-end 75
:internal-dur-at-end 0
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "04"
:orbit-number 3
:pcs-time 195
:si-vis-utilization 3417
:al-overhead-at-end 72
:internal-dur-at-end 0
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)
(Tic-Orbit
:proposal-id 11641
:visit-id "04"
:orbit-number 4
:pcs-time 195
:si-vis-utilization 3415
:al-overhead-at-end 0
:internal-dur-at-end 362
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3614
:pcs-gap 0
)true40PeakUp with the 52x0.1 mask and the mirrorPeakUp with the 52x0.1 mask and the mirror