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My name is Nina Hernitschek. I'm an astronomer interested in solving astronomical big data challenges. Specifically, I like to solve problems requiring computationally efficient machine learning solutions.

Since fall 2019, I'm a DSI/VIDA Postdoctoral Fellow at Vanderbilt University's Data Science Institute (DSI) and the Vanderbilt Initiative in Data-intensive Astrophysics (VIDA). I'm working with Andreas Berlind and Keivan Stassun on astrostatistical methods and astronomical survey science.
Before, I was a postdoc in the Department of Astronomy at Caltech working with Judy Cohen on tidal streams and the Galactic halo.

I'm interested a lot in the dynamical history of our Milky Way - especially halo formation and the disruption of globular clusters and satellites - , which can tell us a lot about galaxy evolution in general.

For my research, I combine this with my passion for solving complex problems, especially my interest in solving big data challenges, which includes machine learning, data stream processing, real-time data processing. I like to develop computationally efficient machine learning methods for handling large time-domain survey datasets. I have expertise in machine learning classification (decision trees such as Random Forest, neural networks etc.), software development/engineering (especially C, C++, Python, Fortran), algorithm design, computational optimization, signal detection, feature extraction & design, big data frameworks (e.g. Kafka, Spark), performance optimisation.

In recent years I developed astrostatistical and machine-learning methods for fast and reliable detection and classification of variable sources in general, including RR Lyrae and QSOs. I applied these methods to the Pan-STARRS survey and a subsequent spectroscopically follow-up survey conducted with Keck and Magellan telescopes (The Caltech/Carnegie Survey of the Outer Halo of the Milky Way). Other research includes data processing and classification for TESS, and a real-time stream broker for ZTF and LSST. For current research, see my publication list.

I'm part of the iPTF/ZTF project and Euclid consortium, as well as TESS and LSST.
Previously I was a PhD student at Max Planck Institut für Astronomie in Heidelberg, Germany (MPIA), working with Prof. Hans-Walter Rix, Eddie Schlafly and Branimir Sesar. During this time, I was a fellow of the International Max Planck Research School (IMPRS).

Aside from research, I also enjoy giving back to people and fueling their curiosity by getting involved in outreach activities. If you are interested in having me as a guest speaker, please let me know.

When I am not working on astronomy-related stuff, I like to go on long hikes to explore the outdoors (and take a bunch of photos), do crafts (mostly painting, woodwork, model making), read Sci-Fi (huge fan of Stephen Baxter), tend a small garden and cook (and try out crazy ingredients).

contact info

nina [dot] hernitschek [at] vanderbilt [dot] edu
techfreaq [at] web [dot] de


github repository

https://github.com/ninahernitschek


Education

since 9/2019: Postdoc at Vanderbilt University, Data Science Fellowship

2/2017 - 9/2019: Postdoc at Caltech

09/2013 to 1/2017: PhD student at MPIA, "Astrophysical Modeling of Time-Domain Surveys", supervisor Hans-Walter Rix

08/2013: M.Sc. Physics, University of Heidelberg, "Estimating Black Hole Masses in Hundreds of Quasars", supervisor Hans-Walter Rix

02/2012: B.Sc. Physics, University of Heidelberg, "Geodesic Lines in Schwarzschild and Kerr Metric", supervisor Matthias Bartelmann

since 2003: worked in several IT projects in industry and research

08/2003: completed 3-year vocational/college training Fachinformatiker (IHK Germany) (IT specialist, software developer)


Research Assistant

03/2011 - 05/2011: Max-Planck-Institut für medizinische Forschung (Max-Planck-Institut for medical research), Heidelberg: Data analysis

02/2010 - 04/2010: Heidelberg Collaboratory for Image Processing, Universität Heidelberg: software developer for advanced driver assistance systems, robotics

08/2008 - 12/2008: Astronomisches Recheninstitut, Heidelberg: software developer for Gaia


Talks and Conferences

LIneA Webinar, invited virtual colloquium talk, November 11 2021

Debating the potential of machine learning in astronomical surveys, virtual poster presentation, October 18-22 2021, https://ml-iap2021.sciencesconf.org/

Twinkle and the Next Generation of Exoplanet Scientists Conference, invited virtual talk, September 2021

LSST enabling science 2021 (2020 Part II) broker workshop, April 13 - 15 2021, virtual meeting, presenting status on LSST alert broker software https://www.lsstcorporation.org/meetings/2021-broker-workshop

University of Notre Dame, invited virtual Astrophysics Seminar talk, March 30 2021

Princeton University, invited virtual Astrophysics Seminar talk, March 18 2021

LSST TVS (Transients and Variable Stars Science Collaboration) Seminar Series, invited virtual talk, February 22 2021

University of Delaware, invited virtual colloquium talk, November 17 2020

237th meeting of the American Astronomical Society, January 11 - 15 2021 https://aas.org/meetings/aas237

IAUS 367: Education and Heritage in the Era of Big Data in Astronomy, December 8 - 12 2020, virtual meeting http://sion.frm.utn.edu.ar/iaus367

LSST enabling science 2020 broker workshop, October 27 - 28 2020, virtual meeting, presenting progress on LSST alert broker software https://www.lsstcorporation.org/meetings/2020-broker-workshop

2020 Accelerated Artificial Intelligence for Big-Data Experiments Conference, October 19 - 21 2020, virtual meeting http://www.ncsa.illinois.edu/Conferences/AcceleratedAINCSA/

Visualization in Astrophysics: Developing New Methods, Discovering Our Universe, Educating the Earth. Part of IEEE VIS 2020, October 25 - 30 2020, virtual meeting http://www.sci.utah.edu/~beiwang/visastro2020/ http://ieeevis.org/year/2020/info/coronavirus-info

2020 Academic Data Science Alliance Annual Meeting, October 14 - 16 2020, virtual meeting, talk https://academicdatascience.org/adsa-meetings/annual-meeting

The Local Group: Assembly and Evolution, August 31 - September 4 2020, virtual meeting hosted by STScI https://www.stsci.edu/contents/events/stsci/2020/april/the-local-group-assembly-and-evolution

Rubin Observatory Project and Community Workshop, August 10 - 14 2020, virtual meeting, presenting LSST alert broker software https://project.lsst.org/meetings/rubin2020

MOBSTER-1 (Magnetic OB[A] Stars with TESS: probing their Evolutionary and Rotational properties) virtual conference, July 13 - 17 2020 , virtual meeting https://sites.google.com/view/mobster1vc/home

Compact Objects and Energetic Phenomena in the Multi-Messenger Era, July 14 - 15 2020, virtual meeting http://www.cvent.com/events/compact-objects-and-energetic-phenomena-in-the-multi-messenger-era/

236th AAS Virtual Meeting, June 1 - 3 2020, Virtually Anywhere https://aas.org/meetings/aas236

RRL/Cep 2019 - Frontiers of Classical Pulsators: Theory and Observations, October 13 - 18 2019, Cloudcroft, New Mexico, US http://rrl2019.nmsu.edu SOC, machine-learning workshop

Annual Keck Science Meeting, September 19 - 20 2019, UCLA, Los Angeles, US https://conferences.pa.ucla.edu/keck-2019/

Hot-Wiring the Transient Universe, August 19 - 22 2019, Northwestern University, Evanston (IL), US, talk http://hotwireduniverse.org/

2019 Santa Cruz Galaxy Workshop, August 5 - 9 2019, UCSC, Santa Cruz, US http://hipacc.ucsc.edu/GalaxyWorkshop2019.html

Astroinformatics 2019, June 24 - 27 2019, Caltech Pasadena http://astroinformatics2019.org/

LSST Community Broker Workshop, June 19 - 21 2019, Seattle (WA), US, talk https://project.lsst.org/meetings/cbw/main

NRC Herzberg colloquium talk, Victoria (BC), 6. Nov. 2018

UBC Astronomy colloquium talk, The University of British Columbia, Vancouver (BC), 5. Nov. 2018

Keck Science Meeting, September 20 - 21 2018, Caltech Pasadena, talk http://www.astro.caltech.edu/ksm2018/?utm_source=Keck+Newsletter&utm_campaign=734fe70835-EMAIL_CAMPAIGN_2018_05_11&utm_medium=email&utm_term=0_5a29392474-734fe70835-48147693

The First Caltech-Swinburne Data Science Workshop, September 18 - 19 2018, Caltech http://www.astro.caltech.edu/workshop/

Caltech AI4Science Workshop, August 1 2018, Caltech https://sites.google.com/view/ai-for-science-workshop/

ZTF Summer School 2018, July 18 - 20 2018, Caltech http://www.ztf.caltech.edu/page/ztfss18agenda

The Second Information Universe Conference, July 3 - 6 2018, Groningen, The Netherlands, talk www.informationuniverse.rug.nl talk streaming

Astrophysical Frontiers in the Next Decade and Beyond: Planets, Galaxies, Black holes & the Transient Universe, June 26 - 29 2018, Portland, Oregon, http://www.cvent.com/events/astrophysical-frontiers-in-the-next-decade-and-beyond-planets-galaxies-black-holes-the-transient-uni/event-summary-bc556bd6b79e4ac1be7db2a2177f1725.aspx

Euclid Consortium Meeting, June 11 - 14 2018, Bonn, Germany https://euclid2018.astro.uni-bonn.de/

Statistical Challenges in 21st Century Cosmology, May 22-25 2018, Valencia, Spain, talk http://cosmo21.cosmostat.org/

SnowPAC 2018: Big Questions, Big Surveys, Big Data: Astronomy & Cosmology in the 2020s, March 11-16 2018, Snowbird, Utah, US, talk http://www.physics.utah.edu/snowpac/

Piercing the Galactic Darkness, October 16-19 2017, Heidelberg, Germany http://www2.mpia-hd.mpg.de/galdark2017/

The RR Lyrae 2017 Conference. Revival of the classical pulsators: from galactic structure to stellar interior diagnostics, September 17-21 2017, Niepolomice, Poland, talk https://www.rrl2017.pl/presentations/talk_Hernitschek.pdf http://www.rrl2017.pl

The 3rd Swinburne-Caltech Workshop: Galaxies and their Halos, September 11-12 2017, Caltech, talk http://astronomy.swin.edu.au/research/conferences/swincaltw3/home.html

Euclid Consortium Meeting "100 years of Lambda", June 5–8 2017, London http://euclid2017.london/

Building the Infrastructure for Time-Domain Alert Science in the LSST Era, May 22-25, Tucson, AZ, USA https://www.noao.edu/meetings/lsst-tds/

ZTF Galactic science workshop, March 13-14 March 2017, Caltech

IAU Symposium 325 on Astroinformatics, October 20-24 2016, Sorrento, Italy; award for best poster presentation

IMPRS Summer School "Astrostatistics & Data Mining", September 12-16 2016, Heidelberg, Germany

ESO Munich Joint Conference "Discs in Galaxies", July 11-15 2016, Garching, Germany https://www.eso.org/sci/meetings/2016/Discs2016.html

LSST@Europe2 Conference, June 20-24 2016, Belgrade, Serbia, invited talk https://project.lsst.org/meetings/lsst-europe-2016/

Heidelberg Physics Graduate Days, April 11-15 2016, Heidelberg http://gsfp.physi.uni-heidelberg.de/graddays

RR Lyrae 2015 Conference "High-precision studies of RR Lyrae stars from dynamical phenomena to mapping the galactic structure", 19-22 October 2015, Visegrad, Hungary, invited talk http://rrl2015.hu/

Astro Hack Week 2015, September 28 - October 02, 2015, New York University http://astrohackweek.github.io/

A 3D View on Galaxy Evolution: from Statistics to Physics, July 6-10 2015, MPIA Heidelberg, Germany http://www2.mpia-hd.mpg.de/~galsp2015/

The Local Group Astrostatistics Conference: Bridging Observations & Simulations, MIRA, University of Michigan, June 1 - 4 2015, talk https://www.lsa.umich.edu/mira/workshopsconferences/localgroupastrostatistics

GC Group Retreat, April 21-23 2015, talk

IMPRS seminar retreat, March 2-4 2015, talk

8th HGSFP Winterschool 2015, University Center Obergurgl, January 31 - February 4 2015, poster presentation poster_variability_hernitschek.pdf

2014 Gaia Challenge, Heidelberg, October 27-31 2014

Science Results from Pan-STARRS1, Space Telescope Science Institute Baltimore, June 23-26, talk https://webcast.stsci.edu/webcast/detail.xhtml?talkid=4150&parent=1

Summer Schools in Statistics & Informatics for Astronomers, Penn State University, June 2-13 2014

The Multi-Wavelength, Multi-Epoch Heritage of Stripe 82, Princeton University, March 2014, poster presentation poster_revmap_hernitschek.pdf

The Galaxy, Stellar Compositions and Dynamics, GREAT-ITN School, IAC (Tenerife, Spain), August 2013


Publications

N. Hernitschek, K. G. Stassun, The Impact of Observing Strategy on Reliable Classification of Standard Candle Stars: Detection of Amplitude, Period, and Phase Modulation (Blazhko Effect) of RR Lyrae Stars with LSST, ApJ accepted for publication (2021) [arXiv:2109.13212 [astro-ph.SR]]

K. Hambleton, F. Bianco, G. Clementini, M. Dall'Ora, R. Egeland, N. Hernitschek et al., Impact of Rubin Observatory LSST Template Acquisition Strategies on Early Science from the Transients and Variable Stars Science Collaboration: Non-time-critical Science Cases, Research Notes of the AAS, 4, 3 (2020) [AJ]

R. A. Arnold, M. V. McSwain, J. Pepper, N. Hernitschek et. al., Long-Period High-Amplitude Red Variables in the KELT Survey, ApJ 247, 2 (2020) [AJ] [arXiv:2001.06498 [astro-ph.SR]]

D. D. Whitten, T. C. Beers, V. M. Placco, R. M. Santucci, P. Denisenkov, P. B. Tissera, N. Hernitschek, Constraints on inner halo assembly history from identification of blue horizontal-branch age gradient and break radius in the inner halo, ApJ 884, 1 (2019) [AJ] [arXiv:1909.12910 [astro-ph.GA]]

D. C. Masters, D. K. Stern, J. G. Cohen, P. L. Capak, S. A. Standord, N. Hernitschek et al., The complete calibration of the color-redshift relation (C3R2) survey: updates, analysis, and Data Release 2, (2019) , ApJ 877, 2 (2019) [AJ] [arXiv:1904.06394 [astro-ph.GA]]

N. Hernitschek, J. G. Cohen, H.-W. Rix et al., Precision distances to dwarf galaxies and globular clusters from Pan-STARRS1 3π RR Lyrae, ApJ 871, 1 (2019) [AJ] [arXiv:1811.10808 [astro-ph.GA]]

M. A. Fardal, R. P. van der Marel, D. R. Law, S. T. Sohn, B. Sesar, N. Hernitschek, H.-W. Rix, Connecting the Milky Way potential profile to the orbital timescales and spatial structure of the Sagittarius Stream, MNRAS 483, 4 (2019) [MNRAS] [arXiv:1804.04995 [astro-ph.GA]]

P. Capak, D. Sconlic, J-C. Cuillandre, F. Castander, A. Bolton, R. Bowler, C. Chang, A. Dey, T. Eifler, D. Eisenstein, C. Grillmair, P. Gris, N. Hernitschek, et al., Mini-survey of the northern sky to Dec <+30, LSST Survey White Paper Submitted in Dec 2018 [arXiv:1904.10438 [astro-ph.IM]]

N. Hernitschek, J. G. Cohen, H.-W. Rix et al., The Profile of the Galactic Halo from Pan-STARRS1 3π RR Lyrae, ApJ 859, 31 (2018) [ApJ] [arXiv:1801.10260 [astro-ph.GA]]

N. Hernitschek, B. Sesar, H.-W. Rix et al., The Geometry of Sagittarius Stream from Pan-STARRS1 3π RR Lyrae, ApJ 850, 96 (2017) [AJ] [arXiv:1710.09436 [astro-ph.GA]]

B. Sesar, N. Hernitschek, M. I. P. Dierickx et al., The > 100 kpc Distant Spur of the Sagittarius Stream and the Outer Virgo Overdensity, as seen in PS1 RR Lyrae stars, AJ 844, L4 (2017) [AJ] [arXiv:1706.10187]

B. Sesar, N. Hernitschek, S. Mitrović, Z. Ivezić et al., Machine-Learned Identification of RR Lyrae Stars from Sparse, Multi-band Data: the PS1 Sample, AJ 153, 5 (2017) [AJ] [arXiv:1611.08596]

N. Hernitschek, H.-W. Rix, E. F. Schlafly, B. Sesar, D. Hogg, Z. Ivezić et al., Finding, characterizing and classifying variable sources in multi-epoch sky surveys: QSOs and RR Lyrae in PS1 3π data, ApJ 817, 73 (2016) [ApJ] [ADS][arXiv/1511.05527]

N. Hernitschek, H.-W. Rix, J. Bovy, & E. Morganson, Estimating Black Hole Masses in Hundreds of Quasars, ApJ 801, 45 (2015) [ApJ] [ADS] [arXiv/1412.6531]

N. Hernitschek, E. Schmidt, M. Vollmer, Lunar eclipse photometry: absolute luminance measurements and modeling, Appl. Optics 47, 62 (2008) [ADS]



Conference Proceedings

N. Hernitschek, B. Sesar, H.-W. Rix, J. G. Cohen (2018), The Geometry of Sagittarius Stream from Pan-STARRS1 3π RR Lyrae In Radek Smolec, Karen Kinemuchi, Richard Anderson (Eds.), The RR Lyrae 2017 Conference. Revival of the Classical Pulsators: from Galactic Structure to Stellar Interior Diagnostics, Proceedings of the Polish Astronomical Society, vol. 6, pp. 72-76 https://www.pta.edu.pl/proc/v6p72

N. Hernitschek, E. F. Schlafly, B. Sesar et al. (2016), Finding, characterizing and classifying variable sources in multi-epoch sky surveys: QSOs and RR Lyraes in PS1 3π In L. Szabados, R. Szabo, K. Kinemuchi (Eds.), RRL2015 High-Precision Studies of RR Lyrae Stars No. 105 COMMUNICATIONS FROM THE KONKOLY OBSERVATORY OF THE HUNGARIAN ACADEMY OF SCIENCES (pp. 85-92) http://www.konkoly.hu/Mitteilungen/Mitt105/105.pdf

N. Hernitschek, E. F. Schlafly, B. Sesar et al. (2016), Pan-STARRS1 as pilot-survey for panoptic time-domain science. Proceedings of the International Astronomical Union, 12(S325), (pp. 118-121). doi:10.1017/S1743921316012667 https://www.cambridge.org/core/journals/proceedings-of-the-international-astronomical-union/issue/E992FC19B0DD8B57AA4FC2F6B58E3FA6


Teaching

supervising undergraduate student 2018
supervising undergraduate studen 2014
Astrolab 02/2014 - 03/2014


Observing

For The Caltech/Carnegie Survey of the Outer Halo of the Milky Way, I regularly observe with MIKE at Magellan (LCO) and ESI at Keck.
For the Euclid project, I regularly observe with ESI and MOSFIRE at Keck to take spectra for photo-z calibration.