Discovery of Brown Dwarfs mining the 2MASS and SDSS databases
Date:
27 Dec 2024 08:31:05
Publisher:
The GAVO DC team
Description:
Brown dwarfs are objects occupying the gap between the least massive
stars and the most massive planets. They are intrinsically faint
objects so their detection is not straighforward and, in fact, was
almost impossible until the advent of global surveys at deep optical
and near-infrared bands like SDSS, 2MASS or DENIS among others. We
propose here to mine the 2MASS-PSC and SDSS-DR9 databases to identify
T-type brown dwarfs through an appropriate combination of colours in
the optical and the infra-red, an approach that perfectly fits into
the Virtual Observatory.
Within this use case for high school students and adanced amateurs
you measure the linear distance of the Andromeda Galaxy following the
steps of the astronomers who first measured it, climbing an important
step of the so-called cosmic distance ladder. The use case requires
the identification of variable stars of the Cepheid class and the
determination of the relation between their period and their intrinsic
luminosity.
Within this use case you learn about supernovae, exploding or
exploded stars. In particular you will use information on the Crab
Nebula (the 1054 aD supernova registered by Chinese astronomers) to
derive its distance: an example of how some very important information
may be gained from very simple arguments and geometry.
The EVN Data Archive's TAP end point. The Table Access
Protocol (TAP) lets you execute queries against our database tables,
inspect various metadata, and upload your own data. It is thus the
VO's premier way to access public data holdings.
Tables exposed through this endpoint include: main from the evn schema, obscore from the ivoa schema, columns, groups, key_columns, keys, schemas, tables from the tap_schema schema.
As stars in open star clusters are formed from the same matter at the
same time and have only a small velocity dispersion, it is relatively
easy to identify them from the background stars. In this tutorial, we
will identify the members of the Pleiades kinematically and get an
idea of our success by examining a color-magnitude diagram using
TOPCAT, Aladin, and a few VO services.
This tutorial uses data from Gaia DR2 to lead you through some of the
capabilities of TOPCAT and STILTS. Use cases covered include a studies
of the globular cluster M4 in proper motion space and the open cluster
Hyades in the full phase space, matches between Gaia and HST data, and
the creation of Hertzsprung-Russell diagrams.
![To the extent possible under law, the publisher has waived all copyright and related or neighboring rights to GAVO's ADQL course. For details, see the `Creative Commons CC0 1.0 Public Domain dedication <http://creativecommons.org/publicdomain/zero/1.0/>`_. Of course, you should still give proper credit when using this data as required by good scientific practice. .. image:: /static/img/cc0.png :alt: [CC0]](/registry-search/?f%5Brights_facet%5D%5B%5D=To+the+extent+possible+under+law%2C+the+publisher+has+waived+all+copyright+and+related+or+neighboring+rights+to+GAVO%27s+ADQL+course.++For+details%2C+see+the+%60Creative+Commons+CC0+1.0+Public+Domain+dedication+%3Chttp%3A%2F%2Fcreativecommons.org%2Fpublicdomain%2Fzero%2F1.0%2F%3E%60_.++Of+course%2C+you+should+still+give+proper+credit+when+using+this+data+as+required+by+good+scientific+practice.%0A%0A..+image%3A%3A+%2Fstatic%2Fimg%2Fcc0.png%0A+++%3Aalt%3A+%5BCC0%5D%0A%0A&f%5Bsubject_facet_lc%5D%5B%5D=virtual-observatories){kind=link}