13,119 research outputs found
Discovery of a Quadruple Lens in CANDELS with a Record Lens Redshift z=1.53
Using spectroscopy from the Large Binocular Telescope and imaging from the
Hubble Space Telescope we discovered the first strong galaxy lens at z(lens)>1.
The lens has a secure photometric redshift of z=1.53+/-0.09 and the source is
spectroscopically confirmed at z=3.417. The Einstein radius (0.35"; 3.0 kpc)
encloses 7.6 x 10^10 Msol, with an upper limit on the dark matter fraction of
60%. The highly magnified (40x) source galaxy has a very small stellar mass
(~10^8 Msol) and shows an extremely strong [OIII]_5007A emission line (EW_0 ~
1000A) bolstering the evidence that intense starbursts among very low-mass
galaxies are common at high redshift.Comment: accepted for publication in ApJ Letter
Recursive formulas for Welschinger invariants of the projective plane
Welschinger invariants of the real projective plane can be computed via the
enumeration of enriched graphs, called marked floor diagrams. By a purely
combinatorial study of these objects, we prove a Caporaso-Harris type formula
which allows one to compute Welschinger invariants for configurations of points
with any number of complex conjugated points.Comment: 18 pages, 2 figure
The Milky Way like galaxy NGC 6384 and its nuclear star cluster at high NIR spatial resolution using LBT/ARGOS commissioning data
We analyse high spatial resolution near infra-red (NIR) imaging of NGC6384, a
Milky Way like galaxy, using ARGOS commissioning data at the Large Binocular
Telescope (LBT). ARGOS provides a stable PSF AO
correction of the ground layer across the LUCI2 NIR camera field
by using six laser guide stars (three per telescope) and a natural guide star
for tip-tilt sensing and guiding. Enabled by this high spatial resolution we
analyse the structure of the nuclear star cluster (NSC) and the central
kiloparsec of NGC6384. We find via 2D modelling that the NSC (pc) is surrounded by a small (pc)
and a larger Sersi\'c (pc), all embedded within the
NGC\,6384 large-scale boxy/X-shaped bulge and disk. This proof-of-concept study
shows that with the high spatial resolution achieved by ground-layer AO we can
push such analysis to distances previously only accessible from space.
SED-fitting to the NIR and optical HST photometry allowed to leverage the
age-metallicity-extinction degeneracies and derive the effective NSC properties
of an young to old population mass ratio of with , Age$_{\rm old,\
young}\!=\!10.9\pm1.3\pm62\%=\!-0.11\pm0.160.33\pm39\%E(B\!-\!V)\!=\!0.63$ and
1.44mag.Comment: 12 pages (+9 appendix), 11 figures, Accepted in MNRA
Pedro Almodóvar and Icíar Bollaín on Gender Violence in Spanish Cinema
This study sought to determine whether Franco-period conservatism and traditionalist values played a role in the portrayal of women, as well as gender violence, in the post-Transition cinema of Pedro Almodóvar and Icíar Bollaín. Four of Almodóvar's movies were studied and categorized in two parts: pre and post 2000's. From Bollaín, three movies were studied, all released after the year 2000. The year 2000 is marked to represent a change in Spanish society's views of gender violence and governmental action was taken to protect women in abusive relationships. The study finds that while traditionalist ideals from the Franco regime are clearly represented in both Almodóvar and Bollaín's films, the purpose is primarily to show a distinction between the oppressive period against women and the obstacles women must battle for equal liberties in relationships and society after the Transition, showing that although Francisco Franco has not been in power, the morals from his time as dictator have a lasting effect on women in Spain.No embargoAcademic Major: Spanis
A K-band spectral mini-survey of Galactic B[e] stars
We present a mini-survey of Galactic B[e] stars mainly undertaken with the
Large Binocular Telescope (LBT). B[e] stars show morphological features with
hydrogen emission lines and an infrared excess, attributed to warm
circumstellar dust. In general, these features are assumed to arise from dense,
non-spherical, disk-forming circumstellar material in which molecules and dust
can condensate. Due to the lack of reliable luminosities, the class of Galactic
B[e] stars contains stars at very different stellar evolutionary phases like
Herbig AeBe, supergiants or planetary nebulae. We took near-infrared long-slit
K-band spectra for a sample of Galactic B[e] stars with the LBT-Luci I.
Prominent spectral features, such as the Brackett gamma line and CO band heads
are identified in the spectra. The analysis shows that the stars can be
characterized as evolved objects. Among others we find one LBV candidate
(MWC314), one supergiant B[e] candidate with 13CO (MWC137) and in two cases
(MWC623 and AS 381) indications for the existence of a late-type binary
companion, complementary to previous studies. For MWC84, IR spectra were taken
at different epochs with LBT-Luci I and the GNIRS spectrograph at the Gemini
North telescope. The new data show the disappearance of the circumstellar CO
emission around this star, previously detectable over decades. Also no signs of
a recent prominent eruption leading to the formation of new CO disk emission
are found during 2010 and 2013.Comment: 10 pages, 7 figures, 4 tables, accepted for publication in MNRAS (in
press
Flame: A Flexible Data Reduction Pipeline for Near-Infrared and Optical Spectroscopy
We present flame, a pipeline for reducing spectroscopic observations obtained
with multi-slit near-infrared and optical instruments. Because of its flexible
design, flame can be easily applied to data obtained with a wide variety of
spectrographs. The flexibility is due to a modular architecture, which allows
changes and customizations to the pipeline, and relegates the
instrument-specific parts to a single module. At the core of the data reduction
is the transformation from observed pixel coordinates (x, y) to rectified
coordinates (lambda, gamma). This transformation consists in the polynomial
functions lambda(x,y) and gamma(x,y) that are derived from arc or sky emission
lines and slit edge tracing, respectively. The use of 2D transformations allows
one to wavelength calibrate and rectify the data using just one interpolation
step. Furthermore, the gamma(x,y) transformation includes also the spatial
misalignment between frames, which can be measured from a reference star
observed simultaneously with the science targets. The misalignment can then be
fully corrected during the rectification, without having to further resample
the data. Sky subtraction can be performed via nodding and/or modeling of the
sky spectrum; the combination of the two methods typically yields the best
results. We illustrate the pipeline by showing examples of data reduction for a
near-infrared instrument (LUCI at the Large Binocular Telescope) and an optical
one (LRIS at the Keck telescope).Comment: 17 pages, 10 figures, published in MNRAS. The pipeline is available
at https://github.com/siriobelli/flam
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