Spacebuzz

Blog posts tagged with spectroscopy

Posts in the past four weeks

Saturday
Sep 27 2014
03:59 UTC

interstellar bands; PSF dictionaries

Gail Zasowski (JHU) gave an absolutely great talk today, about diffuse interstellar bands in the APOGEE spectra and their possible use as tools for mapping the interstellar medium and measuring the kinematics of the Milky Way. Her talk also made it very clear what a huge advance APOGEE is over previous surveys: There are APOGEE stars in the mid-plane of the disk on the other side of the bulge! She showed lots of beautiful data and some results that just scratch the surface of what can be lear

Posted by Hogg's Research

Friday
Sep 26 2014
03:59 UTC

overlapping stars, stellar training sets

On the phone with Schölkopf, Wang, Foreman-Mackey, and I tried to understand how it is that we can fit some insanely variable stars in the Kepler data using other stars, when the variability seems so specific to each star. In one case we investigated, it turned out that the crazy variability of one star (below) was perfectly matched by the variability of another, brighter star. What gives? It turns out that the two stars overlap on the detector, so their footprints actually share pixels!...

Posted by Hogg's Research

Thursday
Sep 25 2014
17:26 UTC

A Deeper Look into the Atmospheres of HR8799 c and d with GPI

... Planet Imager with spectroscopy of the well-studied but not yet well-explained exoplanets HR 8799 c and d.

Posted by astrobites

Thursday
Sep 25 2014
03:59 UTC

deep learning and exoplanet transits

At group meeting, Foreman-Mackey and Wang showed recent results on calibration of K2 and Kepler data, respectively, and Malz showed some SDSS spectra of the night sky. After group meeting, Elizabeth Lamm (NYU) came to ask about possible Data Science capstone projects. We pitched a project on finding exoplanets with Gaia data and another on finding exoplanet transits with deep learning! The latter project was based on Foreman-Mackey's realization that everything that makes convolutional ne

Posted by Hogg's Research

Wednesday
Sep 24 2014
03:59 UTC

half full or half empty?

Interestingly (to me, anyway), as I have been raving in this space about how awesome it is that Ness and I can transfer stellar parameter labels from a small set of "standard stars" to a huge set of APOGEE stars using a data driven model, Rix (who is one of the authors of the method) has been seeing our results as requiring some spin or adjustment in order to be impressive to the stellar parameter community. I see his point: What impresses me is that we get good structure in the label (stellar

Posted by Hogg's Research

Wednesday
Sep 17 2014
03:59 UTC

AstroData Hack Week, day 2

The day started with Huppenkothen (Amsterdam) and I meeting at a caf to discuss what we were going to talk about in the tutorial part of the day. We quickly got derailed to talking about replacing periodograms and auto-correlation functions with Gaussian Processes for finding and measuring quasi-periodic signals in stars and x-ray binaries. We described the simplest possible project and vowed to give it a shot when she arrives at NYU in two months. Immediately following this conversation, w

Posted by Hogg's Research

Wednesday
Sep 10 2014
03:59 UTC

searching in the space of observables

In the early morning, Ness and I talked by phone about The Cannon (or maybe The Jump; guess the source of the name!), our method for providing stellar parameter labels to stars without using stellar models. We talked about possibly putting priors in the label space; this might regularize the results towards plausible values when the data are ambiguous. That's for paper 2, not paper 1. She has drafted an email to the APOGEE-2 collaboration about our current status, and we talked about next

Posted by Hogg's Research

Monday
Sep 08 2014
03:59 UTC

writing

Hidden away in a cabin off the grid, I made writing progress on my project with Ness to make data-driven spectral models, and on my project to use hot planets as clocks for timing experiments. On the latter, I figured out some useful things about expected signal-to-noise and why there is a huge difference between checking local clock rates and looking at global, time-variable timing residuals away from a periodic model.

Posted by Hogg's Research

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