The X-shooter pipeline

Modigliani, A.; Goldoni, P.; Royer, F.; Haigron, R.; Guglielmi, L.; François, P.; Horrobin, M.; Bristow, Paul; Vernet, J.; Moehler, S.; Kerber, F.; Ballester, P.; Mason, E.; Christensen, L.

doi:10.1117/12.857211

Cited by 195 publications

(119 citation statements)

References 7 publications

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“…Data reduction has been carried out using the X-Shooter pipeline (Modigliani et al 2010) version 1.3.7 and the same procedure as in Alcalá et al (2014). For the targets observed on 2010-06-01, 2010-08-20, and 2010-08-28, the photometric standard observed during the night of observation is not supported anymore in the pipeline.…”

Section: Sample Observations and Data Reductionmentioning

confidence: 99%

X-Shooter study of accretion inρ-Ophiucus: very low-mass stars and brown dwarfs

Manara

Testi

Natta

et al. 2015

A&A

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We present new VLT/X-Shooter optical and near-infrared spectra of a sample of 17 candidate young low-mass stars and brown dwarfs located in the ρ-Ophiucus cluster. We derived the spectral type and extinction for all the targets, and then we determined their physical parameters. All the objects but one have M 0.6 M , and eight have mass below or close to the hydrogen-burning limit. Using the intensity of various permitted emission lines present in their spectra, we determined the accretion luminosity and mass accretion rates (Ṁ acc ) for all the objects. When compared with previous works targeting the same sample, we find that, in general, these objects are not as strongly accreting as previously reported, and we suggest that the reason is our more accurate estimate of the photospheric parameters. We also compare our findings with recent works in other slightly older star-forming regions, such as Lupus, to investigate possible differences in the accretion properties, but we find that the accretion properties for our targets have the same dependence on the stellar and substellar parameters as in the other regions. This leads us to conclude that we do not find evidence for a different dependence ofṀ acc with M when comparing low-mass stars and brown dwarfs. Moreover, we find a similar small ( 1 dex) scatter in theṀ acc −M relation as in some of our recent works in other star-forming regions, and no significant differences inṀ acc due to different ages or properties of the regions. The latter result suffers, however, from low statistics and sample selection biases in the current studies. The small scatter in theṀ acc −M correlation confirms that mass accretion rate measurements in the literature based on uncertain photospheric parameters and single accretion indicators, such as the Hα width, can lead to a scatter that is unphysically large. Our studies show that only broadband spectroscopic surveys coupled with a detailed analysis of the photospheric and accretion properties allows us to properly study the evolution of disk accretion rates in star-forming regions.Key words. stars: pre-main sequence -stars: formation -brown dwarfs -protoplanetary disks -accretion, accretion disksopen clusters and associations: individual: rho-Ophiucus IntroductionThe evolution of protoplanetary disks surrounding forming stars has been a major subject of study in recent years. The interest in this topic is driven by the fact that disks are the birthplace of planets. A clear understanding of the physical mechanisms driving the formation, evolution, and dispersal of disks is thus needed to constrain planet formation theories, and to explain the observed properties of our own solar system and of the wealth of exoplanetary systems discovered so far.During their evolution, the central young stellar object (YSO) and the surrounding disk interact through multiple processes, such as photoevaporation, stellar winds, and accretion of matter. The latter is a result of viscous processes happening in the disk, which drive its secular evolu...

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Section: Sample Observations and Data Reductionmentioning

confidence: 99%

X-Shooter study of accretion inρ-Ophiucus: very low-mass stars and brown dwarfs

Manara

Testi

Natta

et al. 2015

A&A

View full text Add to dashboard Cite

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“…A spectrum of a spectrophotometric standard star was taken at the beginning or end of the night. We processed the spectra using version 2.0 of the X-Shooter data reduction pipeline (Goldoni et al 2006;Modigliani et al 2010). The raw frames were first bias subtracted and cosmicray hits were located and removed following the method of van Dokkum (2001).…”

Section: Vlt/x-shootermentioning

confidence: 99%

Are long gamma-ray bursts biased tracers of star formation? Clues from the host galaxies of theSwift/BAT6 complete sample of bright LGRBs

Japelj

Vergani

Salvaterra

et al. 2016

A&A

100

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Aims. Long gamma-ray bursts (LGRBs) are associated with the deaths of massive stars and might therefore be a potentially powerful tool for tracing cosmic star formation. However, especially at low redshifts (z < 1.5) LGRBs seem to prefer particular types of environment. Our aim is to study the host galaxies of a complete sample of bright LGRBs to investigate the effect of the environment on GRB formation. Methods. We studied host galaxy spectra of the Swift/BAT6 complete sample of 14 z < 1 bright LGRBs. We used the detected nebular emission lines to measure the dust extinction, star formation rate (SFR), and nebular metallicity (Z) of the hosts and supplemented the data set with previously measured stellar masses M . The distributions of the obtained properties and their interrelations (e.g. mass-metallicity and SFR-M relations) are compared to samples of field star-forming galaxies. Results. We find that LGRB hosts at z < 1 have on average lower SFRs than if they were direct star formation tracers. By directly comparing metallicity distributions of LGRB hosts and star-forming galaxies, we find a good match between the two populations up to 12 + log O H ∼ 8.4−8.5, after which the paucity of metal-rich LGRB hosts becomes apparent. The LGRB host galaxies of our complete sample are consistent with the mass-metallicity relation at similar mean redshift and stellar masses. The cutoff against high metallicities (and high masses) can explain the low SFR values of LGRB hosts. We find a hint of an increased incidence of starburst galaxies in the Swift/BAT6 z < 1 sample with respect to that of a field star-forming population. Given that the SFRs are low on average, the latter is ascribed to low stellar masses. Nevertheless, the limits on the completeness and metallicity availability of current surveys, coupled with the limited number of LGRB host galaxies, prevents us from investigating more quantitatively whether the starburst incidence is such as expected after taking into account the high-metallicity aversion of LGRB host galaxies.

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“…The data were reduced with the ESO/X-Shooter pipeline v2.5.2 (Modigliani et al 2010) using the Reflex interface (Freudling et al 2013). The spectra have been rectified on a grid with 0.2 Å/pixel in the UVB and VIS arm and 0.6 Å/pixel in the NIR arm, thus slightly oversampling even the highest-resolution spectra while minimizing the correlation between adjacent pixels in the rectification.…”

Section: Sample Descriptionmentioning

confidence: 99%

An X-Shooter composite of bright 1 <z< 2 quasars from UV to infrared

Selsing

Fynbo

Christensen

et al. 2015

A&A

160

180

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Quasi-stellar object (QSO) spectral templates are important both to QSO physics and for investigations that use QSOs as probes of intervening gas and dust. However, combinations of various QSO samples obtained at different times and with different instruments so as to expand a composite and to cover a wider rest frame wavelength region may create systematic effects, and the contribution from QSO hosts may contaminate the composite. We have constructed a composite spectrum from luminous blue QSOs at 1 < z < 2.1 selected from the Sloan Digital Sky Survey (SDSS). The observations with X-Shooter simultaneously cover ultraviolet (UV) to nearinfrared (NIR) light, which ensures that the composite spectrum covers the full rest-frame range from Lyβ to 11 350 Å without any significant host contamination. Assuming a power-law continuum for the composite we find a spectral slope of α λ = 1.70 ± 0.01, which is steeper than previously found in the literature. We attribute the differences to our broader spectral wavelength coverage, which allows us to effectively avoid fitting any regions that are affected either by strong QSO emissions lines (e.g., Balmer lines and complex [Fe II] blends) or by intrinsic host galaxy emission. Finally, we demonstrate the application of the QSO composite spectrum for evaluating the reddening in other QSOs.

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The X-shooter pipeline

Cited by 195 publications

References 7 publications

X-Shooter study of accretion inρ-Ophiucus: very low-mass stars and brown dwarfs

X-Shooter study of accretion inρ-Ophiucus: very low-mass stars and brown dwarfs

Are long gamma-ray bursts biased tracers of star formation? Clues from the host galaxies of theSwift/BAT6 complete sample of bright LGRBs

An X-Shooter composite of bright 1 <z< 2 quasars from UV to infrared

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