Blog posts tagged with spectroscopy

Posts in the past four weeks

Mar 10 2016
04:59 UTC

Kant was wrong?

... the future of stellar spectroscopy. With The Cannon we have shown that detailed abundances can be measured in lower signal-to-noise and lower resolution data than anyone imagined. Now we have to make this case in such a way that we influence future projects!Late in the day, Juna Kollmeier (OCIW) gave a talk at the Simons Foundation. She gave a wide-ranging talk, about gravity from large scales to black holes. The questions were all about Einstein

Posted by Hogg's Research

Mar 09 2016
04:59 UTC

not much

... caught up on backlogs of non-research things today. My research time was spent tweaking our Pigeons-in-holes model for testing MCMC and my visualization of the differences in abundance patterns across supposedly-similar alpha elements.

Posted by Hogg's Research

Mar 08 2016
04:59 UTC

two kinds of alpha elements?

... few days ago I sent around—to the APOGEE Collaboration—plots of large-scale gradients of chemical-abundance ratios in the Milky Way. One of the comments (made by several collaborators) was “that's odd; the alpha elements don't track each other!” I started looking at this today: Can we show that there are multiple kinds of alpha elements? And is that interesting? I made plots of five different [α/Fe] ratios: [O/Fe], [Mg/Fe], [Si/Fe], [S/Fe], and [Ca/Fe

Posted by Hogg's Research

Mar 05 2016
20:25 UTC

Farthest Galaxy Ever Seen Viewed By Hubble Telescope

Since it was first launched in 1990, the Hubble Space Telescope has provided people all over the world with breathtaking views of the Universe. Using its high-tech suite of instruments, Hubble has helped resolve some long-standing problems in astronomy, and helped to raise new questions. And always, its operators have been pushing it to the limit, hoping to gaze farther and farther into the great beyond and see what's lurking there. And as NASA announced with a recent press release, using the HST

Posted by Universe Today

Feb 29 2016
04:59 UTC

short-term plan: solve all of astronomy

On the weekend I had two long conversations with Hans-Walter Rix about the Milky Way chemical abundance ratio gradients that I sent out to the APOGEE Collaboration this past week. Rix's view is that naive interpretation of poorly thought-out gradient estimates would set things in the field back; we should make plots of things that are (as much as possible) easy to predict, and we should interpret them with physically motivated models. I agreed, and that led us down the path of working out the

Posted by Hogg's Research

Feb 22 2016
01:13 UTC

other people's papers

[I spent the last week on vacation, doing only minimal writing and reading.]I spent the weekend working through the draft of Andy Casey's The Cannon 2 paper, in which we use L1 regularization to permit The Cannon to build a model of stellar spectra with dozens of labels (think: abundances). And also Dun Wang's response to referee on the CPM self-calibration of the Kepler data. I also spent some time working out my priorities for March, April, and May.

Posted by Hogg's Research

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