R. M. Wagner

The performance of the blue prime focus large binocular camera at the large binocular telescope

Aims. We present the characteristics and some early scientific results of the first instrument at the Large Binocular Telescope (LBT), the Large Binocular Camera (LBC). Each LBT telescope unit will be equipped with similar prime focus cameras. The blue channel is optimized for imaging in the

Resonance Occupation in the Kuiper Belt: Case Examples of the 5:2 and Trojan Resonances

UV-B

The Deep Ecliptic Survey: A Search for Kuiper Belt Objects and Centaurs. I. Description of Methods and Initial Results

bands and the red channel for imaging in the VRIz bands. The corrected field-of-view of each camera is approximately 30xa0arcmin in diameter, and the chip area is equivalent to a 23

On the distance, reddening and progenitor of V838 Mon

times

V723 CASSIOPEIA STILL ON IN X-RAYS: A BRIGHT SUPER SOFT SOURCE 12 YEARS AFTER OUTBURST

23xa0arcmin 2 field. In this paper we also present the commissioning results of the blue channel. Methods. The scientific and technical performance of the blue channel was assessed by measurement of the astrometric distortion, flat fielding, ghosts, and photometric calibrations. These measurements were then used as input to a data reduction pipeline applied to science commissioning data. Results. The measurements completed during commissioning show that the technical performance of the blue channel is in agreement with original expectations. Since the red camera is very similar to the blue one we expect similar performance from the commissioning that will be performed in the following months in binocular configuration. Using deep UV image, acquired during the commissioning of the blue camera, we derived faint UV galaxy-counts in a ~ 500xa0sq. arcmin sky area to U (Vega) = 26.5. These galaxy counts imply that the blue camera is the most powerful UV imager presently available and in the near future in terms of depth and extent of the field-of-view. We emphasize the potential of the blue camera to increase the robustness of the UGR multicolour selection of Lyman break galaxies at redshift z ~ 3.

New Elemental Abundances for V1974 Cygni

As part of our ongoing Deep Ecliptic Survey (DES) of the Kuiper belt, we report on the occupation of the 1 : 1 (Trojan), 4 : 3, 3 : 2, 7 : 4, 2 : 1, and 5 : 2 Neptunian mean motion resonances (MMRs). The previously unrecognized occupation of the 1 : 1 and 5 : 2 MMRs is not easily understood within the standard model of resonance sweeping by a migratory Neptune over an initially dynamically cold belt. Among all resonant Kuiper belt objects (KBOs), the three observed members of the 5 : 2 MMR discovered by DES possess the largest semimajor axes (a ≈ 55.4 AU), the highest eccentricities (e ≈ 0.4), and substantial orbital inclinations (i ≈ 10°). Objects (38084) 1999HB12 and possibly 2001KC77 can librate with modest amplitudes of ~90° within the 5 : 2 MMR for at least 1 Gyr. Their trajectories cannot be explained by close encounters with Neptune alone, given the latters current orbit. The dynamically hot orbits of such 5 : 2 resonant KBOs, unlike hot orbits of previously known resonant KBOs, may imply that these objects were preheated to large inclination and large eccentricity prior to resonance capture by a migratory Neptune. Our first discovered Neptunian Trojan, 2001QR322, may not owe its existence to Neptunes migration at all. The trajectory of 2001QR322 is remarkably stable; the object can undergo tadpole-type libration about Neptunes leading Lagrange (L4) point for at least 1 Gyr with a libration amplitude of 24°. Trojan capture probably occurred while Neptune accreted the bulk of its mass. For an assumed albedo of 12%–4%, our Trojan is ~130–230 km in diameter. Model-dependent estimates place the total number of Neptune Trojans resembling 2001QR322 at ~20–60. Their existence helps to rule out violent orbital histories for Neptune.

Infrared space observatory and ground-based infrared observations of the classical Nova V723 Cassiopeiae

We report here initial results of the Deep Ecliptic Survey, an ongoing new search for Kuiper belt objects (KBOs) and Centaurs using the 8K × 8K Mosaic CCD array on the 4 m Mayall Telescope at Kitt Peak National Observatory. Within the interval covered in this paper, useful observations were obtained during seven nights in 1998 October and November, 1999 April, and 2000 February. We used a novel technique to efficiently find and determine positions of moving objects. Sixty-nine KBOs and Centaurs with apparent magnitudes between 20.6 and approximately the 24th magnitude were discovered. Nine or 10 of the newly discovered KBOs appear to be in the 3 : 2 mean motion resonance with Neptune, and four appear to be scattered-disk objects. Three objects were found that may be in the 4 : 3 resonance. Sixty-two of the objects reported here have been observed on at least one additional night and have received designations. Our own follow-up astrometry was done primarily with the WIYN 3.5 m telescope in queue-scheduled mode and with the Steward Observatory 90 inch (2.3 m) telescope. Others, using a variety of telescopes, recovered a significant number of our objects. Although not a primary objective of the survey, positions of all main-belt asteroids, Trojan asteroids, and nearby fast-moving asteroids seen in our data also have been determined, and most have been reported to the Minor Planet Center. Through simulations and analysis of the existing KBO database, we have investigated the uncertainty to be expected in various KBO orbital parameters as a function of the extent of the astrometric coverage. The results indicate that the heliocentric distance of an object and the inclination of its orbit can be narrowly constrained with observations from a single apparition. Accurate determination of semimajor axis and eccentricity, on the other hand, requires astrometric data extending over additional apparitions. Based on the observed distribution of orbital inclinations in our sample, we have estimated the true distribution of orbital inclinations in the Kuiper belt and find it to be similar to that of the short-period comets. This result is consistent with the commonly held belief that the Kuiper belt is the source region of the short-period comets.

The Spitzer Infrared Spectrometer view of V4334 Sgr (Sakurai's Object)

Extensive optical and infrared photometry as well as low and high resolution spectroscopy are used as inputs in deriving robust estimates of the reddening, distance and nature of the progenitor of V838 Mon. The reddening is found to obey the R_V=3.1 law and amounts to (i) E(B-V)=0.86 from the interstellar NaI and KI lines, (ii) E(B-V)=0.88 from the energy distribution of the B3V component and (iii) E(B-V)=0.87 from the progression of extinction along the line of sight. The adopted E(B-V)=0.87(+/-0.01) is also the amount required by fitting the progenitor with theoretical isochrones of appropriate metallicity. The distance is estimated from (a) the galactic kinematics of the three components of the interstellar lines, (b) the amount of extinction vs the HI column density and vs the dust emission through the whole Galaxy in that direction, from (c) spectrophotometric parallax to the B3V companion, from (d) comparison of the observed color-magnitude diagram of field stars with 3D stellar population models of the Galaxy, from (e) comparison of theoretical isochrones with the components of the binary system in quiescence and found to be around 10 kpc. Pre-outburst optical and IR energy distributions show that the component erupting in 2002 was brighter and hotter than the B3V companion. The best fit is obtained for a 50,000 K source, 0.5 mag brighter than the B3V companion. Comparison with theoretical isochrones suggests an age of 4 million year for the system and a mass around 65 M(sun) for the progenitor of the outbursting component, which at the time of the outburst was approaching the Carbon ignition stage in its core. The 2002 event is probably just a shell thermonuclear event in the outer envelope of the star.Extensive optical and infrared photometry as well as low and high resolution spectroscopy are used as inputs in deriving robust estimates of the reddening, distance and nature of the progenitor of V838 Mon, the 2002 outbursting event that produced a most spectacular light-echo. The reddening affecting V838 Mon is found to obey the RV = 3.1 law and amounts to (i) EB−V = 0.86 from the interstellar NaI and KI lines; (ii) EB−V = 0.88 from the energy distribution of the B3 V component; and (iii) EB−V = 0.87 from the progression of extinction along the line of sight. The adopted EB−V = 0.87 ± 0.01 is also the amount required by fitting the progenitor with theoretical isochrones of appropriate metallicity. The distance is estimated from (a) the galactic kinematics of the three components of the interstellar lines; (b) the amount of extinction vs. the HI column density and vs. the dust emission through the whole Galaxy in that direction; from (c) spectrophotometric parallax to the B3 V companion; from (d) comparison of the observed color−magnitude diagram of field stars with 3D stellar population models of the Galaxy; from (e) comparison of theoretical isochrones with the components of the binary system in quiescence and found to be around 10 kpc. Pre-outburst optical and IR energy distributions show that the component erupting in 2002 was brighter and hotter than the B3 V companion. The best fit is obtained for a 50 000 K source, 0.5 mag brighter than the B3 V companion. The latter passed unaffected through the outburst, which implies an orbital separation wide enough to avoid mass exchange during the evolution of the binary system, and to allow a safe comparison with theoretical isochrones for single stars. Such a comparison suggests that the progenitor of the outbursting component had an initial mass ∼65 M� ,t hat it was approaching the carbon ignition stage in its core at the time it erupted in 2002 and that the age of the V838 Mon binary system is close to 4 million yr. The 2002 event is probably just a shell thermonuclear event in the outer envelope of the star.

Go Long, Go Deep: Finding Optical Jet Breaks for Swift-Era GRBs with the LBT*

We find that the classical nova V723 Cas (1995) is still an active X-ray source more than 12 years after outburst, and analyze seven X-ray observations carried out with Swift between 2006 January 31 and 2007 December 3. The average count rate is 0.022 ± 0.01 cts s–1, but the source is variable within a factor of 2 of the mean and does not show any signs of turning off. We present supporting optical observations which show that between 2001 and 2006 an underlying hot source was present with steadily increasing temperature. In order to confirm that the X-ray emission is from V723 Cas, we extract a ROSAT observation taken in 1990 and find that there was no X-ray source at the position of the nova. The Swift XRT spectra resemble those of the super soft X-ray binary sources (SSS) which is confirmed by RXTE survey data which show no X-ray emission above 2 keV between 1996 and 2007. Using blackbody fits we constrain the effective temperature to between T eff = (2.8 – 3.8) × 105 K and a bolometric luminosity 5 × 1036 erg s–1 and caution that luminosities from blackbodies are generally overestimated and temperatures underestimated. We discuss a number of possible explanations for the continuing X-ray activity, including the intriguing possibility of steady hydrogen burning due to renewed accretion.

Wide and deep near-UV (360 nm) galaxy counts and the extragalactic background light with the Large Binocular Camera

We present a new analysis of existing optical and ultraviolet spectra of the ONeMg nova V1974 Cygni 1992. Using these data and the photoionization code Cloudy, we have determined the physical parameters and elemental abundances for this nova. Many of the previous studies of this nova have made use of incorrect analyses, and hence a new study was required. Our results show that the ejecta are enhanced, relative to solar, in helium, nitrogen, oxygen, neon, magnesium, and iron. Carbon was found to be subsolar. We find an ejected mass of ~2 × 10-4 M☉. Our model results fit well with observations taken at IR, radio, submillimeter, and X-ray wavelengths.