203,818 research outputs found
Exoplanet Catalogues
One of the most exciting developments in the field of exoplanets has been the
progression from 'stamp-collecting' to demography, from discovery to
characterisation, from exoplanets to comparative exoplanetology. There is an
exhilaration when a prediction is confirmed, a trend is observed, or a new
population appears. This transition has been driven by the rise in the sheer
number of known exoplanets, which has been rising exponentially for two decades
(Mamajek 2016). However, the careful collection, scrutiny and organisation of
these exoplanets is necessary for drawing robust, scientific conclusions that
are sensitive to the biases and caveats that have gone into their discovery.
The purpose of this chapter is to discuss and demonstrate important
considerations to keep in mind when examining or constructing a catalogue of
exoplanets. First, we introduce the value of exoplanetary catalogues. There are
a handful of large, online databases that aggregate the available exoplanet
literature and render it digestible and navigable - an ever more complex task
with the growing number and diversity of exoplanet discoveries. We compare and
contrast three of the most up-to-date general catalogues, including the data
and tools that are available. We then describe exoplanet catalogues that were
constructed to address specific science questions or exoplanet discovery space.
Although we do not attempt to list or summarise all the published lists of
exoplanets in the literature in this chapter, we explore the case study of the
NASA Kepler mission planet catalogues in some detail. Finally, we lay out some
of the best practices to adopt when constructing or utilising an exoplanet
catalogue.Comment: 14 pages, 6 figures. Invited review chapter, to appear in "Handbook
of Exoplanets", edited by H.J. Deeg and J.A. Belmonte, section editor N.
Batalh
Issues in joint SZ and optical cluster finding
We apply simple optical and SZ cluster finders to mock galaxy catalogues and
SZ flux maps created from dark matter halos in a (1 Gpc/h)^3 dark matter
simulation, at redshifts 0.5 and 0.9. At each redshift, the two catalogues are
then combined to assess how well they can improve each other, and compared to
several variants of catalogues made using SZ flux and galaxy information
simultaneously. We use several different criteria to compare the catalogues,
and illustrate some of the tradeoffs which arise in tuning the galaxy cluster
finders with respect to these criteria. We detail many of the resulting
improvements and issues which arise in comparing and combining these two types
of data sets.Comment: 14 pages, added information thanks to helpful suggestions from
refere
The matter distribution in the local Universe as derived from galaxy groups in SDSS DR12 and 2MRS
Context. Friends-of-friends algorithms are a common tool to detect galaxy
groups and clusters in large survey data. In order to be as precise as
possible, they have to be carefully calibrated using mock catalogues.
Aims. We create an accurate and robust description of the matter distribution
in the local Universe using the most up-to-date available data. This will
provide the input for a specific cosmological test planned as follow-up to this
work, and will be useful for general extragalactic and cosmological research.
Methods. We created a set of galaxy group catalogues based on the 2MRS and
SDSS DR12 galaxy samples using a friends-of-friends based group finder
algorithm. The algorithm was carefully calibrated and optimised on a new set of
wide-angle mock catalogues from the Millennium simulation, in order to provide
accurate total mass estimates of the galaxy groups taking into account the
relevant observational biases in 2MRS and SDSS.
Results. We provide four different catalogues (i) a 2MRS based group
catalogue; (ii) an SDSS DR12 based group catalogue reaching out to a redshift z
= 0.11 with stellar mass estimates for 70% of the galaxies; (iii) a catalogue
providing additional fundamental plane distances for all groups of the SDSS
catalogue that host elliptical galaxies; (iv) a catalogue of the mass
distribution in the local Universe based on a combination of our 2MRS and SDSS
catalogues.
Conclusions. While motivated by a specific cosmological test, three of the
four catalogues that we produced are well suited to act as reference databases
for a variety of extragalactic and cosmological science cases. Our catalogue of
fundamental plane distances for SDSS groups provides further added value to
this paper.Comment: 31 pages, 25 figures, accepted for publication in A&
Proper identification of RR Lyrae Stars brighter than 12.5 mag
RR Lyrae stars are of great importance for investigations of Galactic
structure. However, a complete compendium of all RR-Lyraes in the solar
neighbourhood with accurate classifications and coordinates does not exist to
this day. Here we present a catalogue of 561 local RR-Lyrae stars V_max less
equal 12.5 mag according to the magnitudes given in the Combined General
Catalogue of Variable Stars (GCVS) and 16 fainter ones. The Tycho2 catalogue
contains about 100 RR Lyr stars. However, many objects have inaccurate
coordinates in the GCVS, the primary source of variable star information, so
that a reliable cross-identification is difficult. We identified RR Lyrae from
both catalogues based on an intensive literature search. In dubious cases we
carried out photometry of fields to identify the variable. Mennessier and
Colome (2002) have published a paper with Tyc2-GCVS identifications, but we
found that many of their identifications are wrong.
Keywords: astrometry -- Stars: RR Lyrae stars -- Catalogues: Tycho-2
catalogue -- Catalogues: The HST Guide Star Catalogue, Version 1.2 --
Catalogues: Combined General Catalogue of Variable StarsComment: 5 pages with 2 figures; A and A accepted Online-Data are available
under http://www.astro.uni-bonn.de/~gmaint
HerMES: point source catalogues from Herschel-SPIRE observations II
Key Programme on the Herschel Space Observatory. With a wedding cake survey strategy, it consists of nested fields with varying depth and area totalling ∼380 deg2. In this paper, we present deep point source catalogues extracted from Herschel-Spectral and Photometric Imaging Receiver (SPIRE) observations of all HerMES fields, except for the later addition of the 270 deg2 HerMES Large-Mode Survey (HeLMS) field. These catalogues constitute the second Data Release (DR2) made in 2013 October. A sub-set of these catalogues, which consists of bright sources extracted from Herschel-SPIRE observations completed by 2010 May 1 (covering ∼74 deg2) were released earlier in the first extensive data release in 2012 March. Two different methods are used to generate the point source catalogues, the SUSSEXTRACTOR point source extractor used in two earlier data releases (EDR and EDR2) and a new source detection and photometry method. The latter combines an iterative source detection algorithm, STARFINDER, and a De-blended SPIRE Photometry algorithm. We use end-to-end Herschel-SPIRE simulations with realistic number counts and clustering properties to characterize basic properties of the point source catalogues, such as the completeness, reliability, photometric and positional accuracy. Over 500 000 catalogue entries in HerMES fields (except HeLMS) are released to the public through the HeDAM (Herschel Database in Marseille) website (http://hedam.lam.fr/HerMES)
Telescopes don't make catalogues!
Astronomical instruments make intensity measurements; any precise
astronomical experiment ought to involve modeling those measurements. People
make catalogues, but because a catalogue requires hard decisions about
calibration and detection, no catalogue can contain all of the information in
the raw pixels relevant to most scientific investigations. Here we advocate
making catalogue-like data outputs that permit investigators to test hypotheses
with almost the power of the original image pixels. The key is to provide users
with approximations to likelihood tests against the raw image pixels. We
advocate three options, in order of increasing difficulty: The first is to
define catalogue entries and associated uncertainties such that the catalogue
contains the parameters of an approximate description of the image-level
likelihood function. The second is to produce a K-catalogue sampling in
"catalogue space" that samples a posterior probability distribution of
catalogues given the data. The third is to expose a web service or equivalent
that can re-compute on demand the full image-level likelihood for any
user-supplied catalogue.Comment: presented at ELSA 2010: Gaia, at the frontiers of astrometr
On the usefulness of finding charts Or the runaway carbon stars of the Blanco & McCarthy field 37
We have been recently faced with the problem of cross--identifying stars
recorded in historical catalogues with those extracted from recent fully
digitized surveys (such as DENIS and 2MASS). Positions mentioned in the old
catalogues are frequently of poor precision, but are generally accompanied by
finding charts where the interesting objects are flagged. Those finding charts
are sometimes our only link with the accumulated knowledge of past literature.
While checking the identification of some of these objects in several
catalogues, we had the surprise to discover a number of discrepancies in recent
works.The main reason for these discrepancies was generally the blind
application of the smallest difference in position as the criterion to identify
sources from one historical catalogue to those in more recent surveys. In this
paper we give examples of such misidentifications, and show how we were able to
find and correct them.We present modern procedures to discover and solve
cross--identification problems, such as loading digitized images of the sky
through the Aladin service at CDS, and overlaying entries from historical
catalogues and modern surveys. We conclude that the use of good finding charts
still remains the ultimate (though time--consuming) tool to ascertain
cross--identifications in difficult cases.Comment: 4 pages, 1 figure, accepted by A&
A new approach to the assessment of stochastic errors of radio source position catalogues
Assessing the external stochastic errors of radio source position catalogues
derived from VLBI observations is important for tasks such as estimating the
quality of the catalogues and their weighting during combination. One of the
widely used methods to estimate these errors is the three-cornered-hat
technique, which can be extended to the N-cornered-hat technique. A critical
point of this method is how to properly account for the correlations between
the compared catalogues. We present a new approach to solving this problem that
is suitable for simultaneous investigations of several catalogues. To compute
the correlation between two catalogues and , the differences between
these catalogues and a third arbitrary catalogue are computed. Then the
correlation between these differences is considered as an estimate of the
correlation between catalogues and . The average value of these
estimates over all catalogues is taken as a final estimate of the target
correlation. In this way, an exhaustive search of all possible combinations
allows one to compute the paired correlations between all catalogues. As an
additional refinement of the method, we introduce the concept of weighted
correlation coefficient. This technique was applied to nine recently published
radio source position catalogues. We found large systematic differences between
catalogues, that significantly impact determination of their stochastic errors.
Finally, we estimated the stochastic errors of the nine catalogues
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