82 research outputs found
Diffuse interstellar bands {\lambda}5780 and {\lambda}5797 in the Antennae Galaxy as seen by MUSE
ABRIDGED: Diffuse interstellar bands (DIBs) are faint spectral absorption
features of unknown origin. Research on DIBs beyond the Local Group (LG) will
surely blossom in the era of the ELTs. A possibility that needs to be explored
is the use of integral field spectrographs. We do so by using MUSE data for the
Antennae Galaxy, the closest major galaxy merger. High S-to-N spectra were
created by co-adding the signal of many spatial elements. The emission of the
underlying stellar population was modeled using STARLIGHT. To our knowledge, we
have derived the first maps for the DIBs at l5780 and l5797 in galaxies outside
the LG. The l5780 DIB was detected in an area of ~0.6 arcmin2, corresponding to
a linear scale of ~25 kpc2. This region was sampled using >200 independent
lines of sight. The DIB l5797 was detected in >100 independent lines of sight.
Both DIBs are associated with a region with high emission in the HI 21 cm line,
implying a connection between atomic gas and DIBs, as the correlations for the
Milky Way also suggest. Conversely, there is mild spatial association between
the two DIBs and the molecular gas, in agreement with results for our Galaxy
that indicate a lack of correlation between DIBs and molecular gas. The overall
structure for the DIB strength distribution and extinction are comparable.
Within the system, the l5780 DIB clearly correlates with the extinction. Both
DIBs follow the relationship between equivalent width and reddening when data
for several galaxies are considered. Unidentified Infrared emission Bands
(UIBs, likely caused by PAHs) and the l5780 and l5797 DIBs show similar but not
identical spatial distributions. We attribute the differences to extinction
effects without necessarily implying a radically different nature of the
respective carriers. The results illustrate the enormous potential of integral
field spectrographs for extragalactic DIB research.Comment: 12 pages, 13 figures, accepted by Astronomy & Astrophysics; version
corrected by English edito
Resolving stellar populations with integral field spectroscopy
High-performance instruments at large ground-based telescopes have made
integral field spectroscopy (IFS) a powerful tool for the study of extended
objects such as galaxies, nebulae, or even larger survey fields on the sky.
Here we discuss the capabilities of IFS for the study of resolved stellar
populations, using the new method of PSF-fitting crowded field IFS, analogous
to the well-established technique of crowded field photometry with image
sensors. We review early pioneering work with first generation integral field
spectrographs, the breakthrough achieved with the MUSE instrument at the ESO
Very Large Telescope, the remarkable progress accomplished with MUSE in the
study of globular clusters, and first results on nearby galaxies. We discuss
the synergy of integral field spectrographs at 8-10m class telescopes with
future facilities such as the Extremely Large Telescope (ELT).Comment: 6 pages, 3 figures, accepted for AN special issue for
STARS2019/SMFNS201
Recommended from our members
Resolving stellar populations with integral field spectroscopy
High-performance instruments at large ground-based telescopes have made
integral field spectroscopy (IFS) a powerful tool for the study of extended objects
such as galaxies, nebulae, or even larger survey fields on the sky. Here, we discuss
the capabilities of IFS for the study of resolved stellar populations, using the
newmethod of point-spread-function-fitting crowded field IFS, analogous to the
well-established technique of crowded field photometry with image sensors.We
review early pioneering work with first-generation integral field spectrographs,
the breakthrough achieved with the multiunit spectral explorer (MUSE) instrument
at the European Organisation for Astronomical Research in the Southern
Hemisphere (ESO)Very Large Telescope, the remarkable progress accomplished
with MUSE in the study of globular clusters, and first results on nearby galaxies.
We discuss the synergy of integral field spectrographs at 8–10 mclass telescopes
with future facilities such as the extremely large telescope (ELT)
The central dynamics of M3, M13, and M92: Stringent limits on the masses of intermediate-mass black holes
We used the PMAS integral field spectrograph to obtain large sets of radial
velocities in the central regions of three northern Galactic globular clusters:
M3, M13, and M92. By applying the novel technique of crowded field 3D
spectroscopy, we measured radial velocities for about 80 stars within the
central ~ 10 arcsec of each cluster. These are by far the largest spectroscopic
datasets obtained in the innermost parts of these clusters up to now. To obtain
kinematical data across the whole extent of the clusters, we complement our
data with measurements available in the literature. We combine our velocity
measurements with surface brightness profiles to analyse the internal dynamics
of each cluster using spherical Jeans models, and investigate whether our data
provide evidence for an intermediate-mass black hole in any of the clusters.
The surface brightness profiles reveal that all three clusters are consistent
with a core profile, although shallow cusps cannot be excluded. We find that
spherical Jeans models with a constant mass-to-light ratio provide a good
overall representation of the kinematical data. A massive black hole is
required in none of the three clusters to explain the observed kinematics. Our
1sigma (3sigma) upper limits are 5300 M_sun (12000 M_sun) for M3, 8600 M_sun
(13000 M_sun) for M13, and 980 M_sun (2700 M_sun) for M92. A puzzling
circumstance is the existence of several potential high velocity stars in M3
and M13, as their presence can account for the majority of the discrepancies
that we find in our mass limits compared to M92.Comment: accepted for publication in A&A, 20 pages, 15 figures, tables D1 to
D6 only available at CD
Large Velocity Gradients in the Tidal Tails of the Interacting Galaxy AM 1353-272 ("The Dentist's Chair")
We present VLT observations of the interacting system AM 1353-272. Using the
FORS2 instrument, we studied the kinematics of the ionized gas along its
prominent tidal tails and discovered strikingly large velocity gradients
associated with seven luminous tidal knots. These kinematical structures cannot
be caused by streaming motion and most likely do not result from projection
effects. More probably, instabilities in the tidal tails have lead to the
formation of kinematically decoupled objects which could be the progenitors of
self-gravitating Tidal Dwarf Galaxies.Comment: 3 color figures, to appear 10. Nov. 2002 in ApJ
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