References of "Pompei, E"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailESO Spectrophotometry of Comet 9P/Tempel 1
Weiler, M.; Rauer, H.; Sterken, C. et al

in Käufl, H. U.; Sterken, C. (Eds.) Deep Impact as a World Observatory Event: Synergies in Space, Time, and Wavelength (2009)

The Deep Impact target comet 9P/Tempel 1 was observed by means of long-slit spectroscopy from two nights before impact up to eight nights after impact, using the ESO VLT UT1, UT2, and ESO NTT telescopes ... [more ▼]

The Deep Impact target comet 9P/Tempel 1 was observed by means of long-slit spectroscopy from two nights before impact up to eight nights after impact, using the ESO VLT UT1, UT2, and ESO NTT telescopes. Spectra covering the complete optical wavelength range were obtained, and information at different position angles in the coma was collected. The data were used to study the gas and dust activity of comet 9P/Tempel 1. Gas production rates before and after impact and the amount of material in the impact cloud were determined. The pre-impact Afρ parameter, the dust production rate and the dust-to-gas mass ratio were derived. A variation of the cometary gas activity with rotation of the nucleus was detected. A difference in the variation of the brightness of the CN gas emission band compared to the variation of the emissions by C_2, C_3, and NH_2 in the inner coma suggests compositional differences between different parts of the surface of comet 9P/Tempel 1's nucleus. [less ▲]

Detailed reference viewed: 20 (3 ULg)
Full Text
Peer Reviewed
See detailDynamical Modeling of the Deep Impact Dust Ejecta Cloud
Bonev, T.; Ageorges, N.; Bagnulo, S. et al

in Käufl, H. U.; Sterken, C. (Eds.) Deep Impact as a World Observatory Event: Synergies in Space, Time, and Wavelength (2009)

The collision of Deep Impact with comet 9P/Tempel 1 generated a bright cloud of dust which dissipated during several days after the impact. The brightness variations of this cloud and the changes of its ... [more ▼]

The collision of Deep Impact with comet 9P/Tempel 1 generated a bright cloud of dust which dissipated during several days after the impact. The brightness variations of this cloud and the changes of its position and shape are governed by the physical properties of the dust grains. We use a Monte Carlo model to describe the evolution of the post-impact dust plume. The results of our dynamical simulations are compared to the data obtained with FORS2footnote{FORS stands for \underline{FO}cal Reducer and low dispersion Spectrograph for the Very Large Telescope (VLT) of the European Southern Observatory (ESO).} to derive the particle size distribution and the total amount of material contained in the dust ejecta cloud. [less ▲]

Detailed reference viewed: 17 (2 ULg)
Full Text
Peer Reviewed
See detailThe Dusty View of DI from ESO Chile
Boehnhardt, H.; Ageorges, N.; Bagnulo, S. et al

in Käufk, H. U.; Sterken, C. (Eds.) Deep Impact as a World Observatory Event: Synergies in Space, Time, and Wavelength (2009)

Around the time of the impact of NASA's Deep Impact (DI) mission at comet 9P/Tempel 1, in total 6 telescopes with altogether 7 different instruments, located at the La Silla (LSO) and Paranal (VLT ... [more ▼]

Around the time of the impact of NASA's Deep Impact (DI) mission at comet 9P/Tempel 1, in total 6 telescopes with altogether 7 different instruments, located at the La Silla (LSO) and Paranal (VLT) Observatories of the European Southern Observatory (ESO) in Chile, were used to characterize the dust properties before and after the event. The ejecta cloud expanded at an average speed of about 200 ms[SUP]-1[/SUP]during the first hours after the event. It reached stagnation distance of 25000 km about 3 days after impact. The pre-impact dust jet and fan activity (`porcupine' pattern) remained undisturbed after impact. In our measurements the jet activity can be traced to a few 100 km nucleus distance. In total 9 comastructures are identified which may originate from at least 4 regions of enhanced dust emission on the nucleus - one of this region may in fact be multiple. No obvious signatures of a new active region created by DI are found. The overall dust production during the impact compares to about 5-10 h of normal activity. The global expansion geometry of the DI cloud is compatible with a majority of dust grains in the micron size range. Indications exist for asymmetric brightness and colour distributions of the dust in the ejecta cloud. The dust temperature rose from about 280-290 K before to 330 K one day after the event and fell to pre-impact level the day thereafter. The dust reflected sunlight was found to be linearly polarized at about 7.5% in the visible and near-IR, at constant level within about 4000 km from the nucleus. No circular polarization of the dust is detected. [less ▲]

Detailed reference viewed: 27 (4 ULg)
Full Text
Peer Reviewed
See detailIOT Overview: Optical Multi-Object Spectrographs
Schmidtobreick, L.; Bagnulo, S.; Jehin, Emmanuel ULg et al

in Kaufer, A. (Ed.) The 2007 ESO Instrument Calibration Workshop (2008)

We give an introduction to the several instruments that ESO operates and which are able to perform optical multi-object spectroscopy. We point out the standard ways of reducing these spectra, the problems ... [more ▼]

We give an introduction to the several instruments that ESO operates and which are able to perform optical multi-object spectroscopy. We point out the standard ways of reducing these spectra, the problems that occur, and the way we deal with them. A short introduction is given on how the quality control is performed. [less ▲]

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailPhotometry with FORS
Freudling, W.; Møller, P.; Patat, F. et al

in Kaufer, A. (Ed.) The 2007 ESO Instrument Calibration Workshop (2008)

Photometric calibration observations are routinely carried out with all ESO imaging cameras in every clear night. The nightly zeropoints derived from these observations are accurate to about 10%. Recently ... [more ▼]

Photometric calibration observations are routinely carried out with all ESO imaging cameras in every clear night. The nightly zeropoints derived from these observations are accurate to about 10%. Recently, we have started the FORS Absolute Photometry Project (FAP) to investigate, if and how percent-level absolute photometric accuracy can be achieved with FORS1, and how such photometric calibration can be offered to observers. We found that there are significant differences between the sky-flats and the true photometric response of the instrument which partially depend on the rotator angle. A second order correction to the sky-flat significantly improves the relative photometry within the field. We demonstrate the feasibility of percent level photometry and describe the calibrations necessary to achieve that level of accuracy. [less ▲]

Detailed reference viewed: 6 (0 ULg)
Full Text
Peer Reviewed
See detailPhotometric monitoring of the doubly imaged quasar UM 673: possible evidence for chromatic microlensing
Nakos, Theodoros; Courbin, F.; Poels, Joël ULg et al

in Astronomy and Astrophysics (2005), 441

We present the results of two-band CCD photometric monitoring of the gravitationally lensed quasar Q 0142-100 (UM 673). The data, obtained at ESO-La Silla with the 1.54 m Danish telescope in the Gunn i ... [more ▼]

We present the results of two-band CCD photometric monitoring of the gravitationally lensed quasar Q 0142-100 (UM 673). The data, obtained at ESO-La Silla with the 1.54 m Danish telescope in the Gunn i-band (October 1998-September 1999) and in the Johnson V-band (October 1998 to December 2001), were analyzed using three different photometric methods. The light-curves obtained with all methods show variations, with a peak-to-peak amplitude of 0.14 mag in V. Although it was not possible to measure the time delay between the two lensed QSO images, the brighter component displays possible evidence for microlensing: it becomes bluer as it gets brighter, as expected under the assumption of differential magnification of a quasar accretion disk. [less ▲]

Detailed reference viewed: 54 (12 ULg)
Full Text
Peer Reviewed
See detailDeep Impact: Observations from a Worldwide Earth-Based Campaign
Meech, K. J.; Ageorges, N.; A'Hearn, M. F. et al

in Science (2005), 310

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign ... [more ▼]

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics. [less ▲]

Detailed reference viewed: 81 (20 ULg)
Full Text
See detailThe deep impact campaign at ESO: the gas component
Rauer, H.; Jehin, Emmanuel ULg; Manfroid, Jean ULg et al

Poster (2005)

Detailed reference viewed: 5 (0 ULg)
Full Text
Peer Reviewed
See detailAn optical time-delay for the lensed BAL quasar HE 2149-2745
Burud, I.; Courbin, F.; Magain, Pierre ULg et al

in Astronomy and Astrophysics (2002), 383(1), 71-81

We present optical V and i-band light curves of the gravitationally lensed BAL quasar HE 2149-2745. The data, obtained with the 1.5 m Danish Telescope (ESO-La Silla) between October 1998 and December 2000 ... [more ▼]

We present optical V and i-band light curves of the gravitationally lensed BAL quasar HE 2149-2745. The data, obtained with the 1.5 m Danish Telescope (ESO-La Silla) between October 1998 and December 2000, are the first from a long-term project aimed at monitoring selected lensed quasars in the Southern Hemisphere. A time delay of 103+/-12 days is determined from the light curves. In addition, VLT/FORS1 spectra of HE 2149 2745 are deconvolved in order to obtain the spectrum of the faint lensing galaxy, free of any contamination by the bright nearby two quasar images. By cross-correlating the spectrum with galaxy-templates we obtain a tentative redshift estimate of z = 0.495+/-0:01. Adopting this redshift, a Omega = 0.3, Lambda = 0.7 cosmology, and a chosen analytical lens model, our time-delay measurement yields a Hubble constant of H-0 = 66+/-8 km s(-1) Mpc(-1) (1sigma error) with an estimated systematic error of +/-3 km s(-1) Mpc(-1). Using non-parametric models yields H-0 = 65+/-8 km s(-1) Mpc(-1) (1sigma error) and confirms that the lens exhibits a very dense/concentrated mass profile. Finally, we note, as in other cases, that the flux ratio between the two quasar components is wavelength dependent. While the flux ratio in the broad emission lines-equal to 3.7-remains constant with wavelength, the continuum of the brighter component is bluer. Although the data do not rule out extinction of one quasar image relative to the other as a possible explanation, the effect could also be produced by differential microlensing by stars in the lensing galaxy. [less ▲]

Detailed reference viewed: 28 (1 ULg)