scholarly journals The kinematics of local thick discs do not support an accretion origin

2019 ◽  
Vol 623 ◽  
pp. A89 ◽  
Author(s):  
S. Comerón ◽  
H. Salo ◽  
J. H. Knapen ◽  
R. F. Peletier
Keyword(s):  
Formation Mechanism ◽  
Cosmic Time ◽  
Dynamical Friction ◽  
Large Telescope ◽  
Thick Disc ◽  
Numerical Studies ◽  
Very Large Telescope ◽  
Field Unit ◽  
Integral Field ◽  
Do So

Thick discs are nearly ubiquitous components of the discs of present-day galaxies. It has been proposed that a fraction of their stars have been accreted. Here, we aim to find whether accretion of satellites is the main formation mechanism of thick discs. To do so, we observed a sample of eight nearby edge-on galaxies with the Multi-Unit Spectroscopic Explorer (MUSE) integral field unit at the Very Large Telescope (VLT). Six of the galaxies have a distinct thick disc. We derived thick-disc velocities and velocity dispersions for the galaxies in our sample. We devise a formalism to estimate the fractions of retrograde material in the thick discs by using kinematical maps and thin/thick disc decompositions. None of the galaxies in our sample show strong evidence for retrograde material at large distances from the centre. Including those found in the literature, there are seventeen thick discs with studied kinematics, with only one showing unambiguous signatures of retrograde material. Literature numerical studies of dynamical friction allow us to estimate that at the current cosmic time about one in six mergers for which the stars of the accreted galaxy ended in a thick disc were retrograde. This is in tension with the observed fraction of galaxies with a partly retrograde thick disc (one in seventeen). We conclude that satellite accretion is not favoured by observations to be the main formation mechanism of thick discs.

scholarly journals Integral Field Spectroscopy of Planetary Nebulae with MUSE

Galaxies ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 31
Author(s):  
Jeremy R. Walsh ◽  
Ana Monreal-Ibero
Keyword(s):  
Imaging Spectroscopy ◽  
Planetary Nebulae ◽  
Large Telescope ◽  
Advantages And Disadvantages ◽  
Integral Field Spectroscopy ◽  
Very Large Telescope ◽  
The Galaxy ◽  
Field Unit ◽  
Detailed Imaging ◽  
Integral Field

The Multi-Unit Spectroscopic Explorer (MUSE) is a large integral field unit mounted on the ESO Very Large Telescope. Its spatial (60 arcsecond field) and wavelength (4800–9300Å) coverage is well suited to detailed imaging spectroscopy of extended planetary nebulae, such as in the Galaxy. An overview of the capabilities of MUSE applied to Planetary Nebulae (PNe) is provided together with the specific advantages and disadvantages. Some examples of archival MUSE observations of PNe are provided. MUSE datacubes for two targets (NGC 3132 and NGC 7009) are analyzed in detail, and they are used to show the advances achievable for planetary nebula studies. Prospects for further MUSE observations of PNe and a broader analysis of existing datasets are outlined.

scholarly journals Dissecting the turbulent weather driven by mechanical AGN feedback

2020 ◽  
Vol 498 (4) ◽  
pp. 4983-5002
Author(s):  
D Wittor ◽  
M Gaspari
Keyword(s):  
Feedback Loop ◽  
Spatial Scales ◽  
Self Regulation ◽  
Cosmic Time ◽  
Massive Galaxies ◽  
Temporal And Spatial ◽  
Lagrangian Tracers ◽  
Field Unit ◽  
Integral Field ◽  
Gaseous Halo

ABSTRACT Turbulence in the intracluster, intragroup, and circumgalactic medium plays a crucial role in the self-regulated feeding and feedback loop of central supermassive black holes. We dissect the 3D turbulent ‘weather’ in a high-resolution Eulerian simulation of active galactic nucleus (AGN) feedback, shown to be consistent with multiple multiwavelength observables of massive galaxies. We carry out post-processing simulations of Lagrangian tracers to track the evolution of enstrophy, a proxy of turbulence, and its related sinks and sources. This allows us to isolate in depth the physical processes that determine the evolution of turbulence during the recurring strong and weak AGN feedback events, which repeat self-similarly over the Gyr evolution. We find that the evolution of enstrophy/turbulence in the gaseous halo is highly dynamic and variable over small temporal and spatial scales, similar to the chaotic weather processes on Earth. We observe major correlations between the enstrophy amplification and recurrent AGN activity, especially via its kinetic power. While advective and baroclinc motions are always subdominant, stretching motions are the key sources of the amplification of enstrophy, in particular along the jet/cocoon, while rarefactions decrease it throughout the bulk of the volume. This natural self-regulation is able to preserve, as ensemble, the typically observed subsonic turbulence during cosmic time, superposed by recurrent spikes via impulsive anisotropic AGN features (wide outflows, bubbles, cocoon shocks). This study facilitates the preparation and interpretation of the thermo-kinematical observations enabled by new revolutionary X-ray integral field unit telescopes, such as XRISM and Athena.

scholarly journals What can the Occult do for you? STarlight Attenuation & Reddening Survey of Multiple Occulting Galaxies (STARSMOG)

2015 ◽  
Vol 11 (A29B) ◽  
pp. 173-175
Author(s):  
B. W. Holwerda ◽  
W. C. Keel
Keyword(s):  
Interstellar Dust ◽  
High Redshift ◽  
Cosmic Time ◽  
Great Accuracy ◽  
Clear Understanding ◽  
Grain Composition ◽  
Galaxy Type ◽  
Field Unit ◽  
Integral Field

AbstractInterstellar dust is still the dominant uncertainty in Astronomy, limiting precision in e.g., cosmological distance estimates and models of how light is re-processed within a galaxy. When a foreground galaxy serendipitously overlaps a more distant one, the latter backlights the dusty structures in the nearer foreground galaxy. Such an overlapping or occulting galaxy pair can be used to measure the distribution of dust in the closest galaxy with great accuracy. The STARSMOG program uses HST observation of occulting galaxy pairs to accurately map the distribution of dust in foreground galaxies in fine (<100 pc) detail. Furthermore, Integral Field Unit observations of such pairs will map the effective extinction curve in these occulting galaxies, disentangling the role of fine-scale geometry and grain composition on the path of light through a galaxy.The overlapping galaxy technique promises to deliver a clear understanding of the dust in galaxies: the dust geometry, a probability function of the amount of dimming as a function of galaxy type, its dependence on wavelength, and evolution of all these properties with cosmic time using distant, high-redshift pairs.

scholarly journals Raman-scattered laser guide-star photons to monitor the scatter of astronomical telescope mirrors

2018 ◽  
Vol 618 ◽  
pp. L7 ◽  
Author(s):  
Frédéric P. A. Vogt ◽  
José Luis Álvarez ◽  
Domenico Bonaccini Calia ◽  
Wolfgang Hackenberg ◽  
Pierre Bourget ◽  
...  
Keyword(s):  
Dust Particles ◽  
Symbiotic Relationship ◽  
Laser Guide Star ◽  
Large Telescope ◽  
Non Invasive ◽  
Very Large Telescope ◽  
Integral Field Spectrograph ◽  
Guide Star ◽  
Laser Guide ◽  
Integral Field

The first observations of laser guide-star photons that are Raman-scattered by air molecules above the Very Large Telescope (VLT) were reported in June 2017. The initial detection came from the Multi-Unit Spectroscopic Explorer (MUSE) optical integral field spectrograph, following the installation of the 4 Laser Guide Star Facility (4LGSF) on Unit Telescope 4 (UT4) of the VLT. In this Letter, we delve further into the symbiotic relationship between the 4LGSF laser guide-star system, the UT4 telescope, and MUSE by monitoring the spectral contamination of MUSE observations by Raman photons over a 27-month period. This dataset reveals that dust particles deposited on the primary and tertiary mirrors of UT4, which are responsible for a reflectivity loss of ∼8% at 6000 Å, contribute (60 ± 5)% to the laser line fluxes detected by MUSE. The flux of Raman lines, which contaminates scientific observations that are acquired with optical spectrographs, thus provides a new, non-invasive means to monitor the evolving scatter properties of the mirrors of astronomical telescopes that are equipped with laser guide-star systems.

scholarly journals Interstellar medium properties and feedback in local AGN with the MAGNUM survey

2019 ◽  
Vol 15 (S359) ◽  
pp. 323-328
Author(s):  
M. Mingozzi ◽  
G. Cresci ◽  
G. Venturi ◽  
A. Marconi ◽  
F. Mannucci
Keyword(s):  
Interstellar Medium ◽  
Seyfert Galaxies ◽  
Large Telescope ◽  
Novel Approach ◽  
Very Large Telescope ◽  
Central Regions ◽  
Tentative Evidence ◽  
Integral Field Spectrograph ◽  
Integral Field ◽  
Centaurus A

AbstractWe investigated the interstellar medium (ISM) properties in the central regions of nearby Seyfert galaxies characterised by prominent conical or bi-conical outflows belonging to the MAGNUM survey by exploiting the unprecedented sensitivity, spatial and spectral coverage of the integral field spectrograph MUSE at the Very Large Telescope. We developed a novel approach based on the gas and stars kinematics to disentangle high-velocity gas in the outflow from gas in the disc to spatially track the differences in their ISM properties. This allowed us to reveal the presence of an ionisation structure within the extended outflows that can be interpreted with different photoionisation and shock conditions, and to trace tentative evidence of outflow-induced star formation (“positive” feedback) in a galaxy of the sample, Centaurus A.

scholarly journals EAGLE Spectroscopy of Resolved Stellar Populations Beyond the Local Group

2009 ◽  
Vol 5 (S262) ◽  
pp. 299-302
Author(s):  
Chris Evans ◽  
Yanbin Yang ◽  
Mathieu Puech ◽  
Matthew Lehnert ◽  
Michael Barker ◽  
...  
Keyword(s):  
Near Infrared ◽  
Local Group ◽  
Stellar Populations ◽  
Large Telescope ◽  
Design Study ◽  
Local Volume ◽  
Field Unit ◽  
Integral Field

AbstractWe give an overview of the science case for spectroscopy of resolved stellar populations beyond the Local Group with the European Extremely Large Telescope (E-ELT). In particular, we present science simulations undertaken as part of the EAGLE Phase A design study for a multi–integral-field-unit, near-infrared spectrograph. EAGLE will exploit the unprecedented primary aperture of the E-ELT to deliver AO-corrected spectroscopy across a large (38.5 arcmin2) field, truly revolutionising our view of stellar populations in the Local Volume.

SIFUS: SOAR integral field unit spectrograph

2003 ◽  
Author(s):  
Jacques R. D. Lepine ◽  
Antonio C. de Oliveira ◽  
Milito V. Figueredo ◽  
Bruno V. Castilho ◽  
Clemens Gneiding ◽  
...  
Keyword(s):  
Field Unit ◽  
Integral Field

The DIVING3D Project: Analysis of the nuclear region of Early-type Galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 454-456
Author(s):  
T. V. Ricci ◽  
J. E. Steiner ◽  
R. B. Menezes
Keyword(s):  
Emission Lines ◽  
H Ii Regions ◽  
Sample Type ◽  
Early Type ◽  
Integral Field Spectroscopy ◽  
Project Analysis ◽  
Line Region ◽  
Field Unit ◽  
Integral Field

AbstractIn this work, we present preliminary results regarding the nuclear emission lines of a statistically complete sample of 56 early-type galaxies that are part of the Deep Integral Field Spectroscopy View of Nuclei of Galaxies (DIVING3D) Project. All early type galaxies (ETGs) were observed with the Gemini Multi-Object Spectrograph Integral Field Unit (GMOS-IFU) installed on the Gemini South Telescope. We detected emission lines in 93% of the sample, mostly low-ionization nuclear emission-line region galaxies (LINERs). We did not find Transition Objects nor H II regions in the sample. Type 1 objects are seen in ∼23% of the galaxies.

Multiwavelength analysis of OH Megamaser galaxies: The case of IRAS11506-3851

2020 ◽  
Vol 15 (S359) ◽  
pp. 347-349
Author(s):  
Carpes P. Hekatelyne ◽  
Thaisa Storchi-Bergmann
Keyword(s):  
Active Galactic Nuclei ◽  
Hubble Space Telescope ◽  
Galactic Nuclei ◽  
Large Array ◽  
Very Large Array ◽  
Star Forming ◽  
Star Forming Regions ◽  
Field Unit ◽  
Mixed Transition ◽  
Integral Field

AbstractWe present Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU), Hubble Space Telescope (HST) and Very Large Array (VLA) observations of the inner kpc of the OH Megamaser galaxy IRAS 11506-3851. In this work we discuss the kinematics and excitation of the gas as well as its radio emission. The HST images reveal an isolated spiral galaxy and the combination with the GMOS-IFU flux distributions allowed us to identify a partial ring of star-forming regions surrounding the nucleus with a radius of ≍500 pc. The emission-line ratios and excitation map reveal that the region inside the ring present mixed/transition excitation between those of Starbursts and Active Galactic Nuclei (AGN), while regions along the ring are excited by Starbursts. We suggest that we are probing a buried or fading AGN that could be both exciting the gas and originating an outflow.

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