Posted Sep 10, 2022
We have recently made some changes to our observing workstations, retiring several stations and renaming others. The old 32-bit mountain workstations obs2 and obs3 have been retired, and obs4 has been renamed obs-32bit. The former 64-bit machines, obs5 and obs6 have been renamed obs1 & obs2. All observing should be done from these newer 64-bit machines.
Any questions, please contact sciops@lbto.org
Posted Aug 09, 2022
As any user in the NIR astronomical community may already recognize, the resources geared towards near infrared observing are few and far between. The release of Astronomy in the Near-Infrared- Observing Strategies and Data Publications by Dr. Jochen Heidt provides a complete reference for any one preparing, executing, or reducing NIR observations.
Dr. J. Heidt draws from his extensive experience observing with the LBT, outlining examples that many of our users will recognize. This book provides a comprehensive overview of NIR astronomy: from telescope and instrumentation, observing strategies, reduction techniques, and various other considerations associated with such observations. Each chapter is tailored to teach the users of NIR facilities to maximize their scientific output.
Astronomy in the Near-Infrared: Observing Strategies and Data Publications is available for purchase of hardcopy or pdf from Springer at the following link:
Posted Jul 08, 2022
To satisfy the requirements that LBTO data archived and distributed to partners be IVOA-compliant, a WCS was
added to MODS headers at the end of April 2022. MODS data taken on and after 2022-04-29 UT will contain a
spatial WCS with keywords [units]: CTYPE1,2; CRPIX1,2 [pixels]; CRVAL1,2 [degrees]; and the CD matrix [degrees/pixel].
For example, for a recent standard star spectrum, the newly added keyword/values were:
CTYPE1 = ‘RA—TAN’
CTYPE2 = ‘DEC–TAN’
CRPIX1 = 4146.056910569106
CRPIX2 = 1586.024390243902
CRVAL1 = 327.7956677256269
CRVAL2 = 28.86362331864455
CD1_1 = -3.4166666666666E-05
CD1_2 = 0.0
CD2_1 = 0.0
CD2_2 = 3.41666666666666E-05
The decision was made to emulate the WCS in LUCI data, which is also a spatial WCS regardless of whether the data are
imaging and spectroscopic. Before any offsets are made, the values of CRPIX1, CRPIX2 represent the pixel coordinates (x,y)
and the values of CRVAL1, CRVAL2 represent the sky coordinates (ra, dec) at the pointing origin. RADEC offsets will change
the CRVAL1,2 values and DETXY offsets will change the CRPIX1,2 values. The updatepointing command will redefine the current
CRPIX1,2 values as the pointing origin. The CRVAL1,2 values may be helpful when stacking dithered spectra or when interpreting
pseudo-IFU observations where an extended object is dithered across the slit.
Please note, however, that with the addition of a spatial WCS, users may encounter warnings or problems during
the reduction of spectroscopic data:
* With IRAF, at the final stage of extracting a spectrum using apall, there is a warning “Warning: Coordinate system
ignored (rotated?). Using pixel coordinates.” This is harmless and can be ignored.
* The WCS causes problems in the wavelength calibration step of the modsIDL pipeline, and the WCS keywords may need to be
stripped. (Thanks for the report on this).
Please let us know of any warnings or errors encountered when using other tools (pypeIt or another pipeline) to
reduce MODS data with the newly added WCS.
Posted May 12, 2022
Regarding PEPSI scheduling for the remainder of 2022A, the PEPSI team will be conducting their fourth and final run using the 1.8 m VATT plus fiber feed to PEPSI for their TESS campaign tied to ecliptic pole visibility. Their campaign runs inclusively from May 9 through June 30. As a result, the LBTO will need to coordinate as best as possible the use of PEPSI during partner science blocks so that efficient use of PEPSI can be realized. For your PEPSI programs in the upcoming blocks, please let us know any target details and if the observations are time constrained in any way. This request also applies to PEPSI poor weather programs that could be executed on relatively short notice. We thank you for your cooperation.
Posted Apr 05, 2022
The Large Binocular Telescope Interferometer, or LBTI, uses its nulling interferometric capabilities to study the brightness of warm dust floating in the orbital planes of other stars (called exozodiacal dust). In particular, the HOSTS survey (The Hunt for Observable Signatures of Terrestrial Planetary Systems) has studied dust in nearby stars’ habitable zones, where liquid water could exist on the surface of a planet. This project utilized LBTI’s nulling and the unique optical setup of LBTI to execute a large survey of the exozodiacal dust for a number of stars, including sun-like analogs which would be of particular interest for future space-based missions. The habitable zone dust is most emissive around 300K for which LBTI has the greatest sensitivity.
The Large Binocular Telescope on Mount Graham in Arizona. The Milky Way
appears overhead. A dimmer cone of zodiacal light is added for illustration.
(Photo by Ryan Ketterer.)
Interferometric Nulling paves the way, allowing us to separate the star’s overpowering light from the dim glow of circumstellar material. The LBTI Nulling Interferometer works such that the light is simultaneously be collected by two apertures at the end of the interferometer arms. One beam undergoes a half-wavelength phase shift, and combining the beams produces a destructive transmission fringe over the star. Any light fight from an exo-Earth or circumstellar material remains as it would be off-axis. SOUL LBTI AO plays a key role to stabilize the atmospheric perturbations that would otherwise prohibit the imaging of an otherwise “twinkling” star.
The ongoing studies of exo-zodiacal light are critical for finding planets and the studies of habitable zones, as well as for the preparation of space missions. Atmospheric induced noise remains prohibitive for observing rocky planets from the ground in the habitable zone, but pre observations with ground-based observatories using nulling can help guide observations with our space-based telescopes in the decades ahead.
The full Physics Today Paper can be found:
https://physicstoday.scitation.org/doi/full/10.1063/PT.3.4982
Eckhart Spalding, Denis Defrère, Steve Ertel (2022)
Posted Apr 01, 2022
Gamma-ray Bursts (GRBs) are among the brightest and most energetic events in the Universe. There are 2 classifications of these events: Long GRBs (LGRBs) linked with the end states of very massive stars in which the duration of the gamma burst is longer than 2 seconds, and Short GRBs (SGRBs) linked to the mergers of compact objects in which the duration of the gamma burst is two seconds or less. GRB 200826A was detected in August of 2020 and classified as a SGRB. Using the Multi-Object Double Spectrographs (MODS), LBT was the first telescope in the world to determine the event occurred in a galaxy 6.6 billion lightyears away. LBTO staff astronomers working with colleagues in Italy continued to monitor the optical properties of the event. In a series of followup observations, the team used the second generation Single conjugate adaptive Optics Upgrade for LBTO (SOUL) in combination with the LBT Utility Camera in the Infrared (LUCI) to pinpoint the location of the event within the galaxy. as well as measure the size, shape, and mass of the system. This was the first time AO had been used to obtain such detailed information on both the GRB event and the host galaxy. The results from MODS and LUCI-AO demonstrated that GRB 2000826A was the shortest ever GRB event triggered by a supernova, challenging the standard paradigm for SGRB and LGRB progenitors.
Published in the Astrophysical Journal Volume 932 Number 1
A. Rossi, B. Rothberg, E. Palazzi,D. A. Kann, P. D’Avanzo, L. Amati, S. Klose, A. Perego, E. Pian, Guidorzi, A. S. Pozanenko, S. Savaglio, G. Stratta, G. Agapito, S. Covino, F. Cusano, V. D’Elia, M. De Pasquale, M. Della Valle,O. Kuhn, L. Izzo, E. Loffredo,N. Masetti, A. Melandri,P. Y. Minaev,A. Nicuesa Guelbenzu, D. Paris, S. Paiano, C. Plantet, F. Rossi, R. Salvaterra, S. Schulze C. Veillet, and A. A. Volnova
