14768( 2) - 20-Jul-2016 21:15:26 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14768 Version: 2 Check-in Time: 20-Jul-2016 21:15:26 STScI Edit Number: 0 Title UV Signatures of Shock Interaction in an Eta Carinae Analog ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Nathan Smith University of Arizona Y CoI: Dr. Jon Mauerhan University of California - Berkeley N CoI: Dr. Ori Dosovitz Fox Space Telescope Science Institute N CoI: Dr. Jennifer Andrews University of Arizona N ------------------------------------------------------------------------------------ Abstract The optical transient in the dwarf galaxy UGC2773 that was discovered in 2009 (called UGC2773-OT) has proven to be the best known extragalactic analog of the 19th century giant luminous blue variable (LBV) eruption of Eta Carinae. While most non-supernova transients of comparable peak luminosity fade in about 100 days, UGC2773-OT is the only one that has remained in eruption for a decade, like Eta Car. Moreover, spectra of Eta Car's light echoes most closely resemble spectra of UGC2773-OT, and it had a luminous blue progenitor detected by HST. Current debate about Eta Car's eruption centers around it being powered by a super-Eddington wind, or alternatively, an explosion where a shock interacting with dense circumstellar material (CSM) powers the visible display. Interestingly, a recent study of the optical spectra of UGC2773-OT showed evidence of shock emission reminscent of some Type IIn supernovae that are also powered by shock interaction. At visible wavelengths, however, the signatures of a very strong wind can sometimes be similar to those seen in some Type IIn supernovae. Here we propose UV spectroscopy of UGC~2773-OT to either confirm or refute the hypothesis that it has strong shock interaction occuring, by looking for unambiguous UV signatures of shock excitation. While an extremely dense wind with a pseudo photosphere will tend to fall off in flux in the UV due to line blanketing, shock diagnostics like MgII 2800, HeII 1641, and some other lines are expected to be bright in the UV, as they are in Type IIn supernovae. This is a rare opportunity to provide a fairly clean test to discriminate between two quite different models. ------------------------------------------------------------------------------------ Observations Description ------------------------ This program will obtain the NUV and FUV spectrum of the optical transient discovered in the dwarf galaxy UGC2773. Although it was discovered in 2009, the transient had faded very slowly and shows signs of shock interaction in the recent optical spectrum. The purpose of the UV spectra is to determine if the UV sows clear signs of shock excitation or line blanketing from a cool wind. The program will use STIS NUV and FUV MASA detectors with the 230L and 140L elements. ------------------------------------------------------------------------------------ 14768( 2) - 20-Jul-2016 21:15:26 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 UGC-2773-OT STAR, LUMINOUS BLUE RA=03H32M7.2400S, J2000 V = 18.5 +/- 0.5 VARIABLE DEC=+47D47'39.60" Reference Frame: ICRS Extended: NO Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 14768( 2) - 20-Jul-2016 21:15:26 - [ 3] Visit: 01 (NUV) Visit Requirements: BEFORE 01-MAY-2017:00:00:00 On Hold Comments: Additional Comments: 2 orbits, low resolution spectrum. Long-lived transient, but fading. Need to schedule observations as early as possible. 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 UGC-2773-OT STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 5 S (5 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 UGC-2773-OT STIS/NUV ACCUM 52X0.2 G230L 2376 2 1196 S -MAMA (2392 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 UGC-2773-OT STIS/NUV ACCUM 52X0.2 G230L 2376 2 1540 S -MAMA (3080 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 UGC-2773-OT STIS/FUV ACCUM 52X0.2 G140L 1425 2 1480 S -MAMA (2960 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 UGC-2773-OT STIS/FUV ACCUM 52X0.2 G140L 1425 4 1540 S -MAMA (6160 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 | ------------------------------------------------------------------------------------------------------------------------------------ UGC-2773-OT 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A UGC-2773-OT 2 STIS/NUV ACCUM 52X0.2 G230L 2376 none none 1 none 1 N/A -MAMA UGC-2773-OT 2 STIS/NUV ACCUM 52X0.2 G230L 2376 none none 2 none 1 N/A -MAMA UGC-2773-OT 3 STIS/NUV ACCUM 52X0.2 G230L 2376 none none 1 none 2 N/A -MAMA UGC-2773-OT 3 STIS/NUV ACCUM 52X0.2 G230L 2376 none none 2 none 2 N/A -MAMA UGC-2773-OT 4 STIS/FUV ACCUM 52X0.2 G140L 1425 none none 1 none 3 N/A -MAMA UGC-2773-OT 4 STIS/FUV ACCUM 52X0.2 G140L 1425 none none 2 none 3 N/A -MAMA UGC-2773-OT 5 STIS/FUV ACCUM 52X0.2 G140L 1425 none none 1 none 4 N/A -MAMA UGC-2773-OT 5 STIS/FUV ACCUM 52X0.2 G140L 1425 none none 2 none 4 N/A -MAMA UGC-2773-OT 5 STIS/FUV ACCUM 52X0.2 G140L 1425 none none 3 none 5 N/A -MAMA 14768( 2) - 20-Jul-2016 21:15:26 - [ 4] 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 | ------------------------------------------------------------------------------------------------------------------------------------ UGC-2773-OT 5 STIS/FUV ACCUM 52X0.2 G140L 1425 none none 4 none 5 N/A -MAMA 14768( 2) - 20-Jul-2016 21:15:26 - [ 5] Summary Form for Proposal 14768 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BEFORE 01-MAY-2017:00:00:00 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, G230L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names UGC-2773-OT ------------------------------------------------------------------------------------------------------------------------------------