15125( 6) - 06-Nov-2017 11:52:09 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15125 Version: 6 Check-in Time: 06-Nov-2017 11:52:09 STScI Edit Number: 2 Title Galactic fireworks: detecting young stars formed in galactic outflows ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Francesco Belfiore University of California - Santa Cruz Y CoI: Dr. Filippo Mannucci Osservatorio Astrofisico di Arcetri N CoI: Dr. Giovanni Cresci Osservatorio Astrofisico di Arcetri N CoI: Dr. Roberto Maiolino University of Cambridge N CoI: Dr. Santiago Arribas Space Telescope Science Institute - ESA N CoI: Dr. Bethan Lesley James Space Telescope Science Institute - ESA Y CoI: Dr. Helen R Russell University of Cambridge N CoI: Prof. Andrew C. Fabian University of Cambridge N CoI: Dr. Stefano Carniani University of Cambridge N CoI: Dr. Wako Ishibashi Universitat Zurich N CoI: Prof. Alessandro Marconi Universita di Firenze N CoI: Dr. Eckhard Sturm Max-Planck-Institut fur extraterrestrische N Physik CoI: Luis Colina Robledo Centro de Astrobiologia (CSIC/INTA) Inst. N Nac. de Tec. Aero. CoI: Aldrin Flutsch University of Cambridge N ------------------------------------------------------------------------------------ Abstract Recent observations have revealed massive galactic outflows of molecular gas, which may have the physical conditions required to form stars. Since outflows are complex, turbulent, multi-phase media, it has so far been challenging to conclusively identify star formation taking place in the flow via classical diagnostics. By exploiting high resolution, high sensitivity, broad band spectroscopy we have recently found evidence for star formation taking place in the fast galactic outflow of a nearby LIRG. We propose to obtain COS observations with two apertures sampling the outflow of this galaxy with the following goals: (1) obtain a direct detection of the hot, young stars formed in the outflow, which are expected to have the same velocity as the outflowing gas; (2) detect and measure the velocity of the young stars formed in the outer part of the outflow, where, according to models, they should form with velocities higher than the escape velocity; (3) determine the properties of the stars formed in the outflow, in particular their average temperature and metallicity; (4) measure the column density and metallicity of the outflowing gas, and thus constrain the amount of gas in the outflow and, therefore, the efficiency of star formation in this environment. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will observe IRAS2318-59 with an aparture centered on the brightest UV region associated with the southern nucleus (and sampling the inner region of the outflow). 15125( 6) - 06-Nov-2017 11:52:09 - [ 2] We aim at obtaining very high quality spectra, similar or better than those obtained in James et al. (2014), which will enable: (1) a detailed analysis of the velocity profiles and velocity shift of the stellar and ISM absorption features; we plan to compare stellar and ISM kinematics both with each other and with the optical nebular emission and absorption lines tracing the outflow and stellar optical features; (2) disentangle the spectral features associated with the galaxy from the telluric absorption and emission features. In order to achieve these goals we employ an observing strategy similar to James et al. (2014). We will adopt the G130M medium resolution grating (central wavelength at 1291), which covers the CIII 1176 and OIV 1342 young stellar features (in the rest-frame of the galaxy). The medium resolution grating is selected in order to accurately determine the gas kinematics and enable decomposition of line profiles. Given that some of the UV emission is extended on scales of ~1", this will result in to a degradation of the spectral resolution; however, thanks the medium resolution gratings, even with this degradation, the spectral resolution for this component will be still good enough (~60 km/s) to clearly associate the stellar kinematics with the outflow (velocity 300-500 km/s) or with the host galaxy. Also, the medium resolution grating ensures that the spectral features of interest are not blended with MW or telluric lines. The required setting will also enable us to observe numerous ISM lines from various elements in different ionization species and determine their column densities with uncertainties ~0.1 dex through a multi-component fitting technique. We will use the OI 1302 line to determine metallicity. If the line is saturated, we will instead use the SII triplet (1250, 1253, 1259). Based on the ACS F140LP image of the galaxy, the proposed COS aperture has flux F(1500A)~6e-16 erg/s/cm2/AA. In order to perform the detailed analysis discussed above, to disentangle the kinematics of stellar populations with different ages we need to achieve a S/N ~ 15 per spectral resolution element. For the S/N calculation we take as reference wavelengths 1228 AA (which is the observed wavelength of CIII 1176). By using the ETC (with an O9-like spectrum normalized to the fluxes reported above), assuming a point source, the required S/N implies an exposure of 24ks. We use standard peak-up target acquisition (TA) in NUV imaging mode exploiting the bright central UV clump in the proposed aperture. ------------------------------------------------------------------------------------ 15125( 6) - 06-Nov-2017 11:52:09 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 ESO-148-2-PO GALAXY, WIND RA=23H15M46.9020S +/- 0.01", J2000 V = 14.73 INTING-1-INN DEC=-59D03'14.56" +/- 0.01" ER Reference Frame: ICRS Extended: YES Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 15125( 6) - 06-Nov-2017 11:52:09 - [ 4] Visit: 01 (Inner) Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ESO-148-2-P COS/NUV ACQ/IMA PSA MIRRORA 1 80 S (80 OINTING-1-I GE S) NNER ------------------------------------------------------------------------------------------------------------------------------------ 2 ESO-148-2-P COS/FUV TIME-TA PSA G130M 1291 FP-POS=3, FLASH=YES, 1 2646 S OINTING-1-I G BUFFER-TIME=5300 see below NNER (2646 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 ESO-148-2-P COS/FUV TIME-TA PSA G130M 1291 FP-POS=4, FLASH=YES, 1 3163 S OINTING-1-I G BUFFER-TIME=5400 see below NNER (3163 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ESO-148-2-P COS/FUV TIME-TA PSA G130M 1291 FP-POS=3, FLASH=YES, 1 3163 S OINTING-1-I G BUFFER-TIME=5400 see below NNER (3163 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 ESO-148-2-P COS/FUV TIME-TA PSA G130M 1291 FP-POS=4, FLASH=YES, 1 3163 S OINTING-1-I G BUFFER-TIME=5400 see below NNER (3163 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ ESO-148-2-POINTING- 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 1-INNER GE ESO-148-2-POINTING- 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 2646.0 S 1-INNER G ESO-148-2-POINTING- 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 3163.0 S 1-INNER G ESO-148-2-POINTING- 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 3163.0 S 1-INNER G ESO-148-2-POINTING- 5 COS/FUV TIME-TA PSA G130M 1291 none none none none 4 3163.0 S 1-INNER G 15125( 6) - 06-Nov-2017 11:52:09 - [ 5] Visit: 02 (Inner) Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ESO-148-2-P COS/NUV ACQ/IMA PSA MIRRORA 1 80 S (80 OINTING-1-I GE S) NNER ------------------------------------------------------------------------------------------------------------------------------------ 2 ESO-148-2-P COS/FUV TIME-TA PSA G130M 1291 FP-POS=3, FLASH=YES, 1 2646 S OINTING-1-I G BUFFER-TIME=5400 see below NNER (2646 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 ESO-148-2-P COS/FUV TIME-TA PSA G130M 1291 FP-POS=4, FLASH=YES, 1 3163 S OINTING-1-I G BUFFER-TIME=5400 see below NNER (3163 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ESO-148-2-P COS/FUV TIME-TA PSA G130M 1291 FP-POS=3, FLASH=YES, 1 3163 S OINTING-1-I G BUFFER-TIME=5400 see below NNER (3163 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 ESO-148-2-P COS/FUV TIME-TA PSA G130M 1291 FP-POS=4, FLASH=YES, 1 3163 S OINTING-1-I G BUFFER-TIME=5400 (3163 S) NNER ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ ESO-148-2-POINTING- 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A 1-INNER GE ESO-148-2-POINTING- 2 COS/FUV TIME-TA PSA G130M 1291 none none none none 1 2646.0 S 1-INNER G ESO-148-2-POINTING- 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 3163.0 S 1-INNER G ESO-148-2-POINTING- 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 3163.0 S 1-INNER G ESO-148-2-POINTING- 5 COS/FUV TIME-TA PSA G130M 1291 none none none none 4 N/A 1-INNER G 15125( 6) - 06-Nov-2017 11:52:09 - [ 6] Summary Form for Proposal 15125 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=5300, BUFFER-TIME=5400, FLASH=YES, FP-POS=3, FP-POS=4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names ESO-148-2-POINTING-1-INNER ------------------------------------------------------------------------------------------------------------------------------------