Stellar Kinematics Application

Determining ages for brown dwarfs is one of the trickiest aspects in our research, yet a very important one as they allow us to estimate masses. One way many researchers estimate ages is by attempting to match the motions of the object to that of stellar moving groups with known ages. A match in XYZ-UVW space can suggest membership which would imply the brown dwarf is coeval with that group. One can calculate XYZ positions and UVW velocities in Python or your favorite programming language. BDNYC is now hosting a stellar kinematics web application that can do this for you.

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AstrodbWeb

Followers of this blog and our team's scientific endeavors may know we have a curated database of brown dwarfs we work with. An initial version of this database has been published in Filippazzo et al. 2015 and contains information for 198 objects. The database is also maintained on Github, where we welcome contributions from other researchers. We've developed a set of tools for astronomers to work with SQL databases, namely the Python package astrodbkit. This package can be applied to other SQL databases allowing astronomers from all fields of research to manage their data.
Here we introduce a new tool: AstrodbWeb, a web-based interface to explore the BDNYC database.
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BDNYC at MDM

mdm_1

Maybe previous, but never former - once #BDNYC, always #BDNYC!” - Emily Rice

Written By: Stephanie Douglas

The BDNYC group has been around for a while now, and now some of the older members are in positions to provide new opportunities for the current undergrad crowd. Alejandro Núñez and I both joined BDNYC as undergrads: he as a Hunter College student, I as an NSF-funded REU student at the American Museum of Natural History. Then we both chose to do our graduate work at Columbia University - and with the same advisor, Marcel Agüeros. Our group studies rotation and activity in open cluster stars, and we typically receive 10-14 days of time per year on the 2.4m Hiltner telescope at MDM Observatory to take spectra of stars and study their H-alpha emission. This winter, Alejandro and I offered to take along any BDNYC undergrads who were interested in some hands-on observing experience.

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Creating a Database with astrodbkit

The astrodbkit package can be used to modify an existing SQL database (such as The BDNYC Database) but it can also be used to create and populate a SQL database from scratch.

To do this, import the BDdb module and create a new database with
from astrodbkit import astrodb
dbpath = '/path/to/new_database.db'
astrodb.create_databse(dbpath)

Then load your new database with

db = astrodb.Database(dbpath)

and start adding tables! The db.table() method accepts as its arguments the table name, list of field names, and list of data types like so:

db.table('my_new_table', ['field1','field2'], ['INTEGER','TEXT'], new_table=True)

Note new_table=True is necessary to create a new table. Otherwise, it looks for an existing table to modify (which you could do as well!).

To populate your new database with data, read the documentation here or a summary at Adding Data to the BDNYC Database.

As always, I recommend the SQLite Browser for a nice GUI to make changes outside of the command line.

Happy databasing!

BDNYC at CUWiP 2016

The Conference for Undergraduate Women in Physics, or CUWiP, is a set of simultaneous conferences taking place across the United States and supported by the American Physical Society. A variety of activities take place in the conferences including plenary talks, panel discussions, student posters and talks, workshops, and graduate school and career fairs.

This year, BDNYC members Victoria DiTomasso, Haley Fica, and Ellie Schwab attended CUWiP. Victoria and Ellie attended the conference held at Wesleyan University, while Haley attended the one held at Georgia Institute of Technology. All three presented posters on the research they carry out with BDNYC. You can find copies of the posters below.

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Updating the astrodbkit documentation

As you make changes to the astrodbkit repository on Github, you may find that the documentation needs updating. Luckily, we use the invaluable Sphinx and the awesome ReadTheDocs to generate the documentation so this is fairly simple.

First, make sure you update the appropriate doc strings (those informative green bits just below the function definition) as this is what Sphinx will use to generate the documentation!

Start in the top level astrodbkit directory and generate the documentation from the module docstrings with

sphinx-build docs astrodbkit -a

Then cd into the docs directory and rebuild the html files with

cd docs
make html

Now move back to the top level directory and add, commit, and push your changes to Github with something like

cd ..
git add /docs
git commit -m "Updated the documentation for methods x, y, and z."
git push origin <your_branch>

All set! Refresh the page (after a few minutes so ReadTheDocs can build the pages) and make sure everything is to your liking. Well done.

And just in case, here's a great tutorial for getting started with Sphinx and here's the official documentation.

A New Focus for the BDNYC Blog

With this coming year, we are aiming to refocus the content in this blog. While this blog does include general purpose information about brown dwarf research, most of the content was geared towards internal descriptions of our software, our database, and our setup that are relevant only for members of BDNYC. We're now using Trac to manage the internal workings of our team and will be changing some of the content you see on these pages.

From now on, you'll see posts describing general tips and tricks, including coding, project management techniques (such as using Trac), and observing tricks. You'll also see posts announcing team publications as well as team presence at conferences such as AAS. Finally, we hope to publish posts describing the small, incremental steps we take as we carry out our research, which include interesting results and plots.

We hope these changes will result in more frequent posts and will make the blog more valuable to the community as a whole.

BDNYC at Las Campanas Observatory

BDNYC team at Las Campanas Observatory. From left to right: Sara Camnasio, Munazza Alam, Haley Fica, Jackie Faherty

This past September, four members of the BDNYC team travelled to Chile to observe at Las Campanas Observatories (LCO). This team was led by Jackie Faherty and included undergraduate students Munazza Alam, Sara Camnasio, and Haley Fica. Both Munazza and Sara were funded by National Geographic Young Explorers Grants.

Las Campanas Observatories is one of the major telescope facilities in Chile, home to the two Magellan 6.5-meter telescopes and the soon-to-be-constructed Giant Magellan Telescope. For this observing run, the team had a single night on the du Pont 3-meter telescope and two nights on the Baade Magellan telescope. The aim of the run was observing cold brown dwarfs to obtain parallaxes with CAPSCam on the du Pont and FourStar on Baade as well as spectra with FIRE on Baade.

While the weather did not cooperate throughout the run, with a mix of high humidity, high winds, and clouds, that did not deter the team from pushing forward and getting as much data as they could. The all-ladies team has contributed to posts in the Las Campanas Belles blog, which details the adventures of women scientists at Las Campanas and other observatories. The below links direct to each student’s perspective and two summary posts.

Jackie Faherty summary posts:
It's a Ladies Extravaganza at Las Campanas
Thems The Breaks....

Munazza Alam: Maravilla

Sara Camnasio: Setting Foot in Chile (and trying to keep it still)

Haley Fica: A first time Observer