For the best data quality, it is strongly recommended that all four FP-POS positions be used when observing at a given COS CENWAVE setting. For the best data quality, it is strongly recommended that all four FP-POS positions be used when observing at a given COS CENWAVE setting. 0 ----- Attempting Submission 1 (Wed Aug 12 23:52:48 GMT 2015) ----- HST Phase II Proposal 14347 (BDvla23_phase2_jsp1.apt) successfully submitted. Receipt: # 14347-1 ----- Attempting Submission 2 (Thu Mar 31 01:04:33 GMT 2016) ----- Our source is known to be time-variable, possibly characterized by emission bursts - therefore we have endeavored to minimize observational overheads and maximize the use of relatively long, continuous exposures. The inclusion of all four FP-POS locations both increases the breaks in exposure coverage (increasing the likelihood that we could miss a burst event) and does not afford complete spectral coverage in a single G160M CENWAVE setting. As noted in the Observing Description, complete wavelength coverage is necessary to distinguish between physical excitation mechanisms for the auroral emission. Therefore, we have distributed the exposures in FP-POS and CENWAVE to minimize exposure breaks and to provide continuous spectral coverage. We have used three FP-POS settings, split over two cenwave settings to satisfy the above science requirements while minimizing any potential lifetime degradation impact on the COS MCP. In addition to using three FP-POS settings, these observations will have a negligible impact on the long-term gain performance of the MCP for the following reasons: 1) the source flux is <= 1E-14 [erg/cm2/s/A] at all G160M FUV wavelengths, therefore high source count rates will never be realized. 2) these are G160M observations, so there are no significant geocoronal lines that will be imaged onto the detector -- again, high rates on the detector will never be realized for these observations. Over the past decade a small number of very-low mass stars and brown dwarfs have been unexpectedly detected as radio sources (Antonova et al. 2012). Moreover, follow-up observations have revealed coherent, 100% circularly polarized radio pulsed modulated at the 2-3 hour rotational periods of these objects (Hallinan et al. 2007,2008). These observations are consistent with being produced by the electron cyclotron maser instability that produces radio aurorae from magnetized giant planets. Additionally, all of these objects exhibit H-alpha emission which has recently been shown in one example object to be physically associated with the radio aurorae (Hallinan et al. 2015). This evidence points toward a coherent picture of brown dwarf activity as the consequence of large-scale magnetospheric current systems accelerating a population of electrons that precipitate into the brown dwarf upper atmospheres. This same mechanism powers the multi-wavelength aurorae of the magnetized planets in the Solar System. Consequently, we expect the observed brown dwarf radio aurorae to be accompanied by strong aurorae in the FUV. We perform simultaneous observations using the NRAO Very Large Array and the Hubble Space Telescope Cosmic Origins Spectrograph to look for and characterize the ultraviolet aurorae of two brown dwarfs. These observations provide constraints on the properties of the energetic electron beam, the electrodynamic engine and the efficiency of the electron cyclotron maser mechanism. Additionally, these observations allow us to study the upper atmospheres of brown dwarfs and begin exploring auroral physics beyond the Solar System. Brown dwarfs have been recently shown to exhibit strong auroral phenomena at radio and optical wavelengths (Hallinan et al. 2015). These emissions are powered by an accelerated electron beam precipitating into the upper atmosphere, a consequence of large scale magnetospheric current systems. Like the aurorae of the Solar System giant planets, the interaction of the high-energy beam with the molecular hydrogen dominated atmosphere leads to the production of hydrogen Balmer series emission as well as strong emissions at ultraviolet wavelengths. The UV emissions are a consequence of the electron impacts exciting the Lyman and Werner band electronic states of H2 which subsequently emit thousands of narrow molecular emission features between 1200-1650 angstroms. To understand the auroral process in brown dwarfs we are conducting simultaneous observations using the VLA and HST-COS of two auroral brown dwarfs, TVLM513 and LSR1835. Based on the relative energy scaling of the UV and optical emission features of the Jovian aurorae (the best estimate for brown dwarf aurorae), we constructed an electron-impact like H2 UV spectrum with an average flux density of 1e-14 ergs/s/cm2/A between 140.0 nm and 170.0 nm. Using the STScI COS exposure time calculator we determined that the FUV auroral spectrum is readily detectable during the time of a single HST orbit. The emission, however, is rotationally modulated and requires monitoring to insure that we observe it. Our coordinated observations will monitor TVLM513 for 5 hours in the radio and through 2 contiguous orbits with HST as well as LSR1835 for 6.5 hours in the radio and 3 contiguous orbits with HST. These monitoring observations will cover more than a full rotational period of each object (1.97 hrs and 2.84 hrs respectively for TVLM513 and LSR1835) to ensure that we observe the rotationally varying emission despite the observing windows only covering a portion of each orbit. The HST-COS observations will use the G160M grating at the two central wavelength positions 157.7 and 162.3 nm in the TIME-TAG mode through the PSA aperture. The two wavelength settings will allow us to get the full spectrum from 140.0 nm to 180. nm where we expect to see the FUV auroral emission. Operating in TIME-TAG mode will also allow us to discern the time variability of the emission during the long exposures of each orbit. The G160M grating is very sensitive and has a high resolution which is key for observing the faint aurorae and discerning the contribution from the many molecular emission lines. It will also allow us to determine the excitation mechanism of the H2 emission. The UV observations will determine the energetics of the auroral process in brown dwarfs atmospheres and in conjunction with the radio observations allow us to constrain the efficiency of the radio auroral process and the amount of energy in the electron beam. COOL STARS 12 false true false false false false SUPPORTED STAR BROWN DWARF NO Coords/Proper Motions from the Initial Gaia Source List d = 5.7 pc J2000 STAR BROWN DWARF NO d = 10.6pc Coords/Proper Motions from the Initial Gaia Source List J2000 J2000 STAR G V-IV NO NUV GALEX Magnitude of 21.9; SpT about G0 based on SDSS colors sloan g color of 17.203 Necessary offset slew is about 40" J2000 STAR G V-IV NO Has magnitude in Galex NUV, 20.8; -- used as offset acquisition GALEXJ183532.4+325824 Proper Motions from Initial Gaia Source List Necessary Offset Slew 1.8 armin ; SpT about G0 based on B-V J2000 B=15.17 COS/FUV Spectroscopic No No G160M 1589 COS/FUV Spectroscopic No No G160M 1589 1459385933179 The scheduling data was generated by CASM 24.0. CASM was run in Phase II mode. The observing plan will be to split COS G160M observations into two CENWAVE settings (1577 and 1623) at multiple FP-POS positions (1, 2, and 4). This will distribute the photon arrival rate(which will be low for this target) while providing continuous spectral coverage (which is important for distinguishing between H2 excitation mechansims, one of the prime science drivers for this program). The visit will use 3 orbits to observe through the full rotational period of the target and capture rotational modulation of the signal. Target fields have been cleared for bright object concerns. 03/21/16. The target acquisition object has a bright object concern from the GSC catlogue on the offset acquisition target (TVLM-OFFSET), however the same object is cleared by a known GALEX NUV flux. The GSC BOT flag is based on an assumption of a hot O star. The B-V color place the star as an Early G. Even assuming the bright earlier F star, the 100 sec exposure poses no threat to the NUV detector. (Tic-Visit :proposal-id 14347 :visit-id "01" :proposal-version -1 :trans-version "20160129" :date "30-Mar-2016 17:58:52.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 852416 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14347 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14347 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2912 :al-overhead-at-end 0 :internal-dur-at-end 124 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14347 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3023 :al-overhead-at-end 0 :internal-dur-at-end 95 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14347 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3023 :al-overhead-at-end 0 :internal-dur-at-end 388 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) true 3 0 etc run and T_exp estimated from COS.ta.783785 etc run and T_exp estimated fromCOS.sp.783789 etc run and T_exp estimated from COS.sp.737181 etc run and T_exp estimated from COS.sp.737181 1459385934429 The scheduling data was generated by CASM 24.0. CASM was run in Phase II mode. The observing plan will be to split COS G160M observations into two CENWAVE settings (1577 and 1623) at multiple FP-POS positions (1, 2, and 4). This will distribute the photon arrival rate(which will be low for this target) while providing continuous spectral coverage (which is important for distinguishing between H2 excitation mechansims, one of the prime science drivers for this program). The visit will use 2 orbits to observe through the full rotational period of the target and capture rotational modulation of the signal. Target fields have been cleared for bright object concerns. 08/12/15. The target acquisition object has a bright object concern from the GSC catlogue on the offset acquisition target (TVLM-OFFSET), however the same object is cleared by a known GALEX NUV flux. The GSC BOT flag is based on an assumption of a hot O star. The sloan photometery and the B-V color place the star as late F/ Early G. Even assuming the bright earlier F star, the 100 sec exposure poses no threat to the NUV detector. (Tic-Visit :proposal-id 14347 :visit-id "02" :proposal-version -1 :trans-version "20160129" :date "30-Mar-2016 17:58:54.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 530656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14347 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14347 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2883 :al-overhead-at-end 0 :internal-dur-at-end 67 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14347 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3000 :al-overhead-at-end 0 :internal-dur-at-end 388 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) false 2 0 etc run and T_exp estimated from COS.ta.737169 etc run and T_exp estimated from COS.sp.737174 etc run and T_exp estimated from COS.sp.737175 etc run and T_exp estimated from COS.sp.737176