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The TESS Ten Thousand Catalog: 10,001 uniformly-vetted and -validated Eclipsing Binary Stars detected in Full-Frame Image data by machine learning and analyzed by citizen scientists

Kostov, Veselin B., Powell, Brian P., Fornear, Aline U., Di Fraia, Marco Z., Gagliano, Robert, Jacobs, Thomas L., de Lambilly, Julien S., Luca, Hugo A. Durantini, Majewski, Steven R., Omohundro, Mark, Orosz, Jerome, Rappaport, Saul A., Salik, Ryan, Short, Donald, Welsh, William, Alexandrov, Svetoslav, da Silva, Cledison Marcos, Dunning, Erika, Guhne, Gerd, Huten, Marc, Hyogo, Michiharu, Iannone, Davide, Lee, Sam, Magliano, Christian, Sharma, Manya, Tarr, Allan, Yablonsky, John, Acharya, Sovan, Adams, Fred, Barclay, Thomas, Montet, Benjamin T., Mullally, Susan, Olmschenk, Greg, Prsa, Andrej, Quintana, Elisa, Wilson, Robert, Balcioglu, Hasret, Kruse, Ethan, Collaboration, the Eclipsing Binary Patrol

arXiv.org Artificial Intelligence

The Transiting Exoplanet Survey Satellite (TESS) has surveyed nearly the entire sky in Full-Frame Image mode with a time resolution of 200 seconds to 30 minutes and a temporal baseline of at least 27 days. In addition to the primary goal of discovering new exoplanets, TESS is exceptionally capable at detecting variable stars, and in particular short-period eclipsing binaries which are relatively common, making up a few percent of all stars, and represent powerful astrophysical laboratories for deep investigations of stellar formation and evolution. We combed Sectors 1-82 of TESS Full-Frame Image data searching for eclipsing binary stars using a neural network that identified ~1.2 million stars with eclipse-like features. Of these, we have performed an in-depth analysis on ~60,000 targets using automated methods and manual inspection by citizen scientists. Here we present a catalog of 10001 uniformly-vetted and -validated eclipsing binary stars that passed all our ephemeris and photocenter tests, as well as complementary visual inspection. Of these, 7936 are new eclipsing binaries while the remaining 2065 are known systems for which we update the published ephemerides. We outline the detection and analysis of the targets, discuss the properties of the sample, and highlight potentially interesting systems. Finally, we also provide a list of ~900,000 unvetted and unvalidated targets for which the neural network found eclipse-like features with a score higher than 0.9, and for which there are no known eclipsing binaries within a sky-projected separation of a TESS pixel (~21 arcsec).


The Detection of KIC 1718360, A Rotating Variable with a Possible Companion, Using Machine Learning

Roche, Jakob

arXiv.org Artificial Intelligence

This paper presents the detection of a periodic dimming event in the lightcurve of the G1.5IV-V type star KIC 1718360. This is based on visible-light observations conducted by both the TESS and Kepler space telescopes. Analysis of the data seems to point toward a high rotation rate in the star, with a rotational period of 2.938 days. The high variability seen within the star's lightcurve points toward classification as a rotating variable. The initial observation was made in Kepler Quarter 16 data using the One-Class SVM machine learning method. Subsequent observations by the TESS space telescope corroborated these findings. It appears that KIC 1718360 is a nearby rotating variable that appears in little to no major catalogs as such. A secondary, additional periodic dip is also present, indicating a possible exoplanetary companion.


Photo-zSNthesis: Converting Type Ia Supernova Lightcurves to Redshift Estimates via Deep Learning

Qu, Helen, Sako, Masao

arXiv.org Artificial Intelligence

Upcoming photometric surveys will discover tens of thousands of Type Ia supernovae (SNe Ia), vastly outpacing the capacity of our spectroscopic resources. In order to maximize the science return of these observations in the absence of spectroscopic information, we must accurately extract key parameters, such as SN redshifts, with photometric information alone. We present Photo-zSNthesis, a convolutional neural network-based method for predicting full redshift probability distributions from multi-band supernova lightcurves, tested on both simulated Sloan Digital Sky Survey (SDSS) and Vera C. Rubin Legacy Survey of Space and Time (LSST) data as well as observed SDSS SNe. We show major improvements over predictions from existing methods on both simulations and real observations as well as minimal redshift-dependent bias, which is a challenge due to selection effects, e.g. Malmquist bias. Specifically, we show a 61x improvement in prediction bias on PLAsTiCC simulations and 5x improvement on real SDSS data compared to results from a widely used photometric redshift estimator, LCFIT+Z. The PDFs produced by this method are well-constrained and will maximize the cosmological constraining power of photometric SNe Ia samples.


Coding for the cosmos - Microsoft Garage

#artificialintelligence

Microsoft, NASA, and students from two HBCUs in the Reston/DC area have completed the maiden mission of a new Microsoft/NASA partnership, STEM Educational Project: AI looking for new Earths. Using methodology developed by The Microsoft Garage over years of running hackathons, in just one month – and while completing their final exams – the student hackers learned and deployed several new technologies, and quite literally reached the stars by showing they could deploy code to the International Space Station. According to Piali Ghose, Director of The Garage Reston/DC and host of the event, "This hackathon amplifies the cultural priorities closest to our hearts here at Microsoft and at The Garage because it allows us to continue fulfilling our stated commitments to making a difference, seeking diversity and being inclusive in our work, bringing multiple teams together as'One Microsoft' while collaborating with federal and academic partners, and doing all of this with a growth mindset." The partnership emerged from a shared goal of fostering the future STEM workforce by exposing university students to science, tools, and expertise "at the intersection of Space Cloud." By structuring the project as a month-long hackathon, participating students learned how real data scientists work as a team to ideate, develop, and validate their work with a proof of concept.


The effect of phased recurrent units in the classification of multiple catalogs of astronomical lightcurves

Donoso-Oliva, C., Cabrera-Vives, G., Protopapas, P., Carrasco-Davis, R., Estevez, P. A.

arXiv.org Artificial Intelligence

In the new era of very large telescopes, where data is crucial to expand scientific knowledge, we have witnessed many deep learning applications for the automatic classification of lightcurves. Recurrent neural networks (RNNs) are one of the models used for these applications, and the LSTM unit stands out for being an excellent choice for the representation of long time series. In general, RNNs assume observations at discrete times, which may not suit the irregular sampling of lightcurves. A traditional technique to address irregular sequences consists of adding the sampling time to the network's input, but this is not guaranteed to capture sampling irregularities during training. Alternatively, the Phased LSTM unit has been created to address this problem by updating its state using the sampling times explicitly. In this work, we study the effectiveness of the LSTM and Phased LSTM based architectures for the classification of astronomical lightcurves. We use seven catalogs containing periodic and nonperiodic astronomical objects. Our findings show that LSTM outperformed PLSTM on 6/7 datasets. However, the combination of both units enhances the results in all datasets.


Exoplanet Detection using Machine Learning

#artificialintelligence

We introduce a new machine learning based technique to detect exoplanets using the transit method. Machine learning and deep learning techniques have proven to be broadly applicable in various scientific research areas. We aim to exploit some of these methods to improve the conventional algorithm based approach used in astrophysics today to detect exoplanets. We used the popular time-series analysis library'TSFresh' to extract features from lightcurves. For each lightcurve, we extracted 789 features.


Distinguishing short and long $Fermi$ gamma-ray bursts

Tarnopolski, Mariusz

arXiv.org Machine Learning

Two classes of gamma-ray bursts (GRBs), short and long, have been determined without any doubts, and are usually ascribed to different progenitors, yet these classes overlap for a variety of descriptive parameters. A subsample of 46 long and 22 short $Fermi$ GRBs with estimated Hurst Exponents (HEs), complemented by minimum variability time-scales (MVTS) and durations ($T_{90}$) is used to perform a supervised Machine Learning (ML) and Monte Carlo (MC) simulation using a Support Vector Machine (SVM) algorithm. It is found that while $T_{90}$ itself performs very well in distinguishing short and long GRBs, the overall success ratio is higher when the training set is complemented by MVTS and HE. These results may allow to introduce a new (non-linear) parameter that might provide less ambiguous classification of GRBs.


An improved quasar detection method in EROS-2 and MACHO LMC datasets

Pichara, Karim, Protopapas, Pavlos, Kim, Dae-Won, Marquette, Jean-Baptiste, Tisserand, Patrick

arXiv.org Machine Learning

We present a new classification method for quasar identification in the EROS-2 and MACHO datasets based on a boosted version of Random Forest classifier. We use a set of variability features including parameters of a continuous auto regressive model. We prove that continuous auto regressive parameters are very important discriminators in the classification process. We create two training sets (one for EROS-2 and one for MACHO datasets) using known quasars found in the LMC. Our model's accuracy in both EROS-2 and MACHO training sets is about 90% precision and 86% recall, improving the state of the art models accuracy in quasar detection. We apply the model on the complete, including 28 million objects, EROS-2 and MACHO LMC datasets, finding 1160 and 2551 candidates respectively. To further validate our list of candidates, we crossmatched our list with a previous 663 known strong candidates, getting 74% of matches for MACHO and 40% in EROS-2. The main difference on matching level is because EROS-2 is a slightly shallower survey which translates to significantly lower signal-to-noise ratio lightcurves.