COS observations of a very young massive star cluster in the blue compact dwarf galaxy NGC 5253

0 Assigned ID: 1129 ----- Attempting Submission 1 (Fri Sep 27 13:29:17 GMT 2019) ----- HST Phase I Proposal 1129 (N5253-12.apt) successfully submitted. Receipt: # 1129-1 ----- Attempting Submission 2 (Fri Sep 27 19:14:30 GMT 2019) ----- HST Phase I Proposal 1129 (N5253-12.apt) successfully submitted. Receipt: # 1129-2 ----- Attempting Submission 3 (Fri Sep 27 21:14:27 GMT 2019) ----- HST Phase I Proposal 1129 (N5253-12.apt) successfully submitted. Receipt: # 1129-3 The BOT tool is inadequate for checking the field because of the resolution. There is an SBC image (F125LP) (ID 11579) which shows all targets are safe. 604076848 ----- Attempting Submission 1 (Thu Dec 05 20:08:11 GMT 2019) ----- COS observations of a very young massive star cluster in the blue compact dwarf galaxy NGC 5253 A high gas pressure environment is thought to be a prerequisite for both the formation of globular clusters in redshift > 2 galaxies and young massive star clusters (YMCs) in the nearby universe. Such high pressures are rare in the quiescent disks of nearby galaxies and YMCs are usually confined to galaxy mergers, starburst dwarf galaxies and nuclear regions where pressures are high. Local YMCs are excellent analogs to the proto-GCs that are now being discovered at high redshift through gravitational lensing. Since JWST will obtain rest-frame UV spectra of star-forming clumps/proto-GCs in high redshift galaxies, it is essential to obtain FUV spectra of YMCs in nearby galaxies, while we still have access to the UV domain. We have recently discovered a very young (< 1 Myr) massive star cluster close to the starburst core of the blue compact dwarf galaxy NGC 5253. We are asking for mid-cycle time for FUV COS spectroscopy because finding such a rare, young cluster still associated with its natal molecular cloud and observable at FUV wavelengths is potentially unique. FUV spectra of this cluster will be an essential addition to current COS surveys of young clusters in nearby galaxies. We will perform a detailed investigation of both the stellar content and the cluster wind interaction with the interstellar medium. We will determine the age and obtain information on the IMF by searching for the signature of very massive stars. The COS FUV spectrum will act as a benchmark for high redshift studies by defining the FUV spectral characteristics of massive stars at the youngest ages, and the importance of early feedback on the ISM. This program obtains COS spectroscopy of cluster #12 in NGC 5253 with the G130M and G160M gratings. The target is acquired using an offset star to ensure that cluster #12 is properly centered. The offset star is acquired via ACQ/IMAGE, the offset is performed and a short NUV imaging exposure of cluster #12 is taken using ACCUM. The first visit consists of TIME-TAG exposures with G130M/1291 (FP-POS 3,4) for 4 orbits and the second visit with G160M/1600 (FP-POS=1,2,3,4) for another 4 orbits. The exposure times are calculated to provide a S/N of 8 using WFC3/F275W=17.82, a SSP of 5 Myr and E(B-V)=0.28. We are all experts in the research area of young massive clusters in nearby galaxies. We have used both the imaging and spectroscopic instruments on HST to study YMCs. We are also experts on the FUV spectra of massive star popluations and the interaction of their winds with the surrounding interstellar medium. Between us, we have published well over 200 papers in the subject area of the proposal. Stellar Populations 6 false false true false false false false SUPPORTED STELLAR CLUSTER STAR FORMING REGION NO J2000 F275W=17.82 STAR UNDESIGNATED NO Coords are from Gaia DR2. Quoted V mag is GAIA G band mag which is close to Johnson V. J2000 WFC3/UVIS F275W mag = 19.07 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G160M 1600 1575574793672 The scheduling data was generated by CASM 27.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16045 :visit-id "01" :proposal-version -1 :trans-version "20190514" :date "05-Dec-2019 14:39:52.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 235088 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16045 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16045 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2787 :al-overhead-at-end 0 :internal-dur-at-end 57 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16045 :visit-id "01" :orbit-number 2 :pcs-time 302 :si-vis-utilization 2878 :al-overhead-at-end 0 :internal-dur-at-end 57 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16045 :visit-id "01" :orbit-number 3 :pcs-time 302 :si-vis-utilization 2878 :al-overhead-at-end 0 :internal-dur-at-end 57 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16045 :visit-id "01" :orbit-number 4 :pcs-time 302 :si-vis-utilization 2878 :al-overhead-at-end 0 :internal-dur-at-end 350 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) true 4 0 Used F275W mag and O5V SED with E(B-V)=0 Used F275W mag =17.82, SSP 5 Myr SED with E(B-V)=0.28. NUV image of cluster and surrounding field. 1575505272145 The scheduling data was generated by CASM 27.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16045 :visit-id "02" :proposal-version -1 :trans-version "20190514" :date "04-Dec-2019 19:21:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 104768 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16045 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16045 :visit-id "02" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2787 :al-overhead-at-end 0 :internal-dur-at-end 38 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16045 :visit-id "02" :orbit-number 2 :pcs-time 302 :si-vis-utilization 2878 :al-overhead-at-end 0 :internal-dur-at-end 38 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16045 :visit-id "02" :orbit-number 3 :pcs-time 302 :si-vis-utilization 2878 :al-overhead-at-end 0 :internal-dur-at-end 38 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16045 :visit-id "02" :orbit-number 4 :pcs-time 302 :si-vis-utilization 2878 :al-overhead-at-end 0 :internal-dur-at-end 331 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) true 4 0 Used F275W mag and O5V SED with E(B-V)=0 Used F275W mag =17.82, SSP 5 Myr SED with E(B-V)=0.28. NUV image of cluster and surrounding field.