11 research outputs found
Gathering Galaxy Distances in Abundance with Roman Wide-Area Data
The extragalactic distance scale is fundamental to our understanding of
astrophysics and cosmology. In recent years, the surface brightness fluctuation
(SBF) method, applied in the near-IR, has proven especially powerful for
measuring galaxy distances, first with HST and now with a new JWST program to
calibrate the method directly from the tip of the red giant branch (TRGB). So
far, however, the distances from space have been gathered slowly, one or two at
a time. With the Roman Space Telescope, we have the opportunity to measure
uniformly high-quality SBF distances to thousands of galaxies out to hundreds
of Mpc. The impact of these data on cosmology and galaxy studies depends on the
specifics of the survey, including the filter selection, exposure depth, and
(especially) the sky coverage. While the baseline HLWAS survey in four filters
plus the grism would yield useful data, the impact would be limited by the
relatively small area. A more optimal approach would concentrate on the most
efficient passband (F146), adopt an exposure time sufficient to measure good
quality distances well out into the Hubble flow, and then maximize the sky
coverage within the total time constraints. Grism observations over the same
area can provide the needed information on redshifts and spectral energy
distributions for compact sources, while colors for larger objects can be
obtained from lower resolution surveys. The proposed plan will enable accurate
determination of the physical properties of thousands of nearby galaxies, an
independent measure of the Hubble constant with negligible statistical
error, and competitive constraints on .
The resulting data set will be a phenomenal resource for a wide range of
studies in astrophysics and cosmology.Comment: 5 pages; submitted to the call for Roman Core Community Survey white
paper
Science with the Einstein Telescope: a comparison of different designs
The Einstein Telescope (ET), the European project for a third-generation
gravitational-wave detector, has a reference configuration based on a
triangular shape consisting of three nested detectors with 10 km arms, where in
each arm there is a `xylophone' configuration made of an interferometer tuned
toward high frequencies, and an interferometer tuned toward low frequencies and
working at cryogenic temperature. Here, we examine the scientific perspectives
under possible variations of this reference design. We perform a detailed
evaluation of the science case for a single triangular geometry observatory,
and we compare it with the results obtained for a network of two L-shaped
detectors (either parallel or misaligned) located in Europe, considering
different choices of arm-length for both the triangle and the 2L geometries. We
also study how the science output changes in the absence of the low-frequency
instrument, both for the triangle and the 2L configurations. We examine a broad
class of simple `metrics' that quantify the science output, related to compact
binary coalescences, multi-messenger astronomy and stochastic backgrounds, and
we then examine the impact of different detector designs on a more specific set
of scientific objectives.Comment: 197 pages, 72 figure
A study of globular clusters in a lenticular galaxy in Hydra I from deep HST/ACS photometry
We take advantage of exquisitely deep optical imaging data from HST/ACS in
the F475W () and F606W () bands, to study the properties
of the globular cluster (GC) population in the intermediate mass lenticular
galaxy PGC 087327, in the Hydra I galaxy cluster. We inspect the photometric
(magnitudes and color) and morphometric (compactness, elongation, etc.)
properties of sources lying in an area of kpc centered on PGC
087327, and compare them with four neighbouring fields over the same HST/ACS
mosaic. This allowed us to identify a list of GC candidates and to inspect
their properties using a background decontamination method. Relative to the
four comparison fields, PGC 087327 shows a robust overdensity of GCs,
. At the estimated magnitude of the galaxy, this number implies
a specific frequency of . In spite of the short wavelength
interval available with the and passbands, the color
distribution shows a clear bimodality with a blue peak at mag and a red peak at mag. We also observe the typical
steeper slope of the radial distribution of red GCs relative to blue ones.
Thanks to the unique depth of the available data, we characterize the GC
luminosity function (GCLF) well beyond the expected GCLF turn-over. We find
mag and
mag, which after calibration yields a distance of Mpc.Comment: Accepted for publication in A&
The Wide-field Spectroscopic Telescope (WST) Science White Paper
The Wide-field Spectroscopic Telescope (WST) is proposed as a new facility dedicated to the efficient delivery of spectroscopic surveys. This white paper summarises the initial concept as well as the corresponding science cases. WST will feature simultaneous operation of a large field-of-view (3 sq. degree), a high multiplex (20,000) multi-object spectrograph (MOS) and a giant 3x3 sq. arcmin integral field spectrograph (IFS). In scientific capability these requirements place WST far ahead of existing and planned facilities. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work synergistically with future ground and space-based facilities. This white paper shows that WST can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; origin of stars and planets; time domain and multi-messenger astrophysics. WST's uniquely rich dataset will deliver unforeseen discoveries in many of these areas. The WST Science Team (already including more than 500 scientists worldwide) is open to the all astronomical community. To register in the WST Science Team please visit https://www.wstelescope.com/for-scientists/participat
The Wide-field Spectroscopic Telescope (WST) Science White Paper
The Wide-field Spectroscopic Telescope (WST) is proposed as a new facility dedicated to the efficient delivery of spectroscopic surveys. This white paper summarises the initial concept as well as the corresponding science cases. WST will feature simultaneous operation of a large field-of-view (3 sq. degree), a high multiplex (20,000) multi-object spectrograph (MOS) and a giant 3x3 sq. arcmin integral field spectrograph (IFS). In scientific capability these requirements place WST far ahead of existing and planned facilities. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work synergistically with future ground and space-based facilities. This white paper shows that WST can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; origin of stars and planets; time domain and multi-messenger astrophysics. WST's uniquely rich dataset will deliver unforeseen discoveries in many of these areas. The WST Science Team (already including more than 500 scientists worldwide) is open to the all astronomical community. To register in the WST Science Team please visit https://www.wstelescope.com/for-scientists/participat
The Wide-field Spectroscopic Telescope (WST) Science White Paper
The Wide-field Spectroscopic Telescope (WST) is proposed as a new facility dedicated to the efficient delivery of spectroscopic surveys. This white paper summarises the initial concept as well as the corresponding science cases. WST will feature simultaneous operation of a large field-of-view (3 sq. degree), a high multiplex (20,000) multi-object spectrograph (MOS) and a giant 3x3 sq. arcmin integral field spectrograph (IFS). In scientific capability these requirements place WST far ahead of existing and planned facilities. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work synergistically with future ground and space-based facilities. This white paper shows that WST can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; origin of stars and planets; time domain and multi-messenger astrophysics. WST's uniquely rich dataset will deliver unforeseen discoveries in many of these areas. The WST Science Team (already including more than 500 scientists worldwide) is open to the all astronomical community. To register in the WST Science Team please visit https://www.wstelescope.com/for-scientists/participat
The Wide-field Spectroscopic Telescope (WST) Science White Paper
The Wide-field Spectroscopic Telescope (WST) is proposed as a new facility dedicated to the efficient delivery of spectroscopic surveys. This white paper summarises the initial concept as well as the corresponding science cases. WST will feature simultaneous operation of a large field-of-view (3 sq. degree), a high multiplex (20,000) multi-object spectrograph (MOS) and a giant 3x3 sq. arcmin integral field spectrograph (IFS). In scientific capability these requirements place WST far ahead of existing and planned facilities. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work synergistically with future ground and space-based facilities. This white paper shows that WST can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; origin of stars and planets; time domain and multi-messenger astrophysics. WST's uniquely rich dataset will deliver unforeseen discoveries in many of these areas. The WST Science Team (already including more than 500 scientists worldwide) is open to the all astronomical community. To register in the WST Science Team please visit https://www.wstelescope.com/for-scientists/participat
The Wide-field Spectroscopic Telescope (WST) Science White Paper
The Wide-field Spectroscopic Telescope (WST) is proposed as a new facility dedicated to the efficient delivery of spectroscopic surveys. This white paper summarises the initial concept as well as the corresponding science cases. WST will feature simultaneous operation of a large field-of-view (3 sq. degree), a high multiplex (20,000) multi-object spectrograph (MOS) and a giant 3x3 sq. arcmin integral field spectrograph (IFS). In scientific capability these requirements place WST far ahead of existing and planned facilities. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work synergistically with future ground and space-based facilities. This white paper shows that WST can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; origin of stars and planets; time domain and multi-messenger astrophysics. WST's uniquely rich dataset will deliver unforeseen discoveries in many of these areas. The WST Science Team (already including more than 500 scientists worldwide) is open to the all astronomical community. To register in the WST Science Team please visit https://www.wstelescope.com/for-scientists/participat