-
a Professor in JMU’s Physics
and Astronomy Department
where she teaches physics and
astronomy classes, and conducts research on galaxies that host supermassive black holes in their centers.
bio
at a Glance
Prof. Constantin received her Bachelor of Science in physics at the University of Bucharest where she specialized in molecular and atomic physics and Astrophysics. After a few years of high school physics teaching, she completed her PhD in astrophysics at Ohio University, as well as postdoctoral positions at Drexel
University and Harvard-Smithsonian Center for
Astrophysics, before joining James Madison University in
2009. Prof. Constantin’s
galactic
investigations
involve
identifying
telltales of
the processes
by which black
holes form and
grow, which
most often
require new
observations
from
observatories
like the
Hubble Space
Telescope, the
Chandra Space Observatory, the MMT Observatories, the W.M. Keck and
the Gemini North Observatories, as
well as the largest steerable radio telescope in the world, the GBT in WV.
Check out the Research
page
for some insights into her work.
Prof. Constantin
takes a tremendous
amount of joy from
engaging in scientific
discovery the future
generations of
decision makers. Thus,
in addition to being a
scientist and an
educator,
Prof. Constantin
coaches and mentors
young people in their
career journeys, both
through novel outreach
programs and via individual personalized interactions.
The lullabies Prof. Constantin’s daughter heard when she was little included often some sort of cosmic perspectives… literally!
Research
Prof. Constantin’s investigations, together with collaborators across the globe, and students (mainly in the JMU – astro lab) are pushing back the frontier of what we know about centers of galaxies from observing the obvious luminous sources. Prof. Constantin is studying galaxies via a wide variety of the properties of Active Galactic Nuclei (AGN), which are believed to be the energetic manifestation of supermassive black hole accretion. The ultimate research goal is to understand the factors that determine the existence of an accreting central massive black hole (i.e., an AGN) in some galaxies and not in others, and the factors that distinguish among AGN phenomena at different cosmological epochs.
Here are some highlights of my work:
A seminal work connecting the
black hole accretion phenomenon to circumnuclear star formation
in what appears to be the faintest active galactic nuclei; this
investigation compares the nuclear emission as seen from the
ground with the MMT with
sharper observationsfrom HST
which revealed density and temperature gradients, as well as
evidence for decade long variability, that offer better
constraints for the nature of various levels of observed
accretion onto SMBHs in galaxy centers;
The Astrophysical Journal, Vol 814, 2
A novel
statistical analysis of multi-wavelength properties of the
galaxies that host water maser emission, with the main goal of
significantly improving their detection rate, that is crucial
for accurate determination of the Hubble constant and
characterization of dark energy, also revealed new connections
between the water maser morphology and the type of gas
ionization and excitation that happens in galaxy centers;
The
Astrophysical Journal, Vol. 860, 169; The
Astrophysical Journal, Vol. 892, 18; The
Astrophysical Journal, Vol. 819, 1
A campaign on understanding the nuclear
activity of the galaxies inhabiting the most under-dense regions
of the universe, the cosmic voids, unveiled peculiar but crucial
aspects of the environmental dependence of the cosmic galactic
evolution.
Most importantly, we might have provided some interesting
constraints to the various phases galaxies go through in their
evolution from young spirals to old red ellipticals, and to
the rate this evolution might happen in extremely different
density environments; The
Astrophysical Journal, Vol. 673, 2, The
Astrophysical Journal, Vol. 810, 165
The discovery of a system of three actively accreting
supermassive black holes within a system of gravitationaly
interacting galaxies: this proves that the moderm theory of
the universe, which predicted systems like this, works! There
is a lot of dust in the universe, and especially in
interacting galaxy systmes, making these kinds of discoveries
really challenging, and super rarities. We have
employed here a smart combination of observations from accross
the whole electromagnetic spectrum, from Chandra (soft X-rays)
and NuStar (hard X-rays)
observatories to the big ol' telescopes like the Large
Binocular Telescope (near infrared) and the SDSS (visible), to prove the existence of
(hidden) accretion in these three galactic nuclei;
The Astrophysical Journal, Vol. 883, 11
Using the largest curated sample of X-ray
detections of galaxies in the nearby Universe from Chandra Space
Telescope, and visible light observations from the Sloan Digital Sky
Survey, we explored in detail the balance of power provided by
nuclear star formation and by accretion of matter onto central supermassive
black holes in galaxies today (which can be different from how
things might have happened in the past, when the universe was much
younger). We discovered that one likely scenario entails a
transition from powerful star formation, followed by a gradual
increase in the dominance of the light emitted by black hole
accretion until a maximum strength is achieved, after which stellar
populations become older and therefore weaker in producing hot
photons, along with a waning of the power of accretion as well,
leading to a passive galaxy state. The details of such an
evolutionary scenario are facsinating, and are continously
challenged by new observaitosn and theoretical models;
; The Astrophysical Journal, Vol. 705, 2
Teaching
I marvel at how the objective reality of the universe comprises the subjective reality of every one of us. Thus, I am continuously baffled by how unintegrated science is into the rest of human affairs, how stubbornly apart from the world it remains, and how persistent is the idea that appreciation of science is something to be outgrown by all but those odd rare nerds, like me. ”We are the universe, and by studying the universe we ultimately turn the mirror on ourselves,” I often tell to whomever cares to listen to me.
For me now, to pursue scholarship in teaching and discovery in
astrophysics means to empower my students to embrace complexity, to
read the world attentively and with curiosity, and to respond in
meaningful ways that honor our complexity. I believe I am able to
stress the importance of context and the power of recognizing
non-obvious patterns, so I design ways of making the right
connection. I prioritize experiential learning, problem-solving
skills, and help my students practice the art of inquiry. I develop experiences where they could focus on their own searches for answers, methods, and even ideas. I allow them to explore and exploit their own tools. I offer them the satisfaction of explaining their own findings. I have them set up telescopes to discover the sky in a way they had never had the chance to do it before. To my suggestions to choreograph gravitational waves, to sing about the Mars missions, to paint or recite poetry about collisions of galaxies, to convert scientific inquiry into social media interactions, they respond with ambition, joy, and curiosity.
Here are some examples of the outcomes of a novel project component that encourages creative expression in a
scientific context, where students are asked to prove their understanding
and ability to communicate recent astronomy-related successes. The
assignment starts with reading popular-level articles, upon which they are asked to answer a set of
questions that require them to combine their knowledge (from this
course) and their own conclusions from the article, while given
complete freedom to the medium used to implement the final product:
* Dance on Mars , by Taylor Bess
(JMU junior, Justice Studies, with Vocal Performance by Valerie
Westerman, JMU junior), Nov. 2014
* Martian Air , by Louis
Gaertner (JMU junior, Political Science), Nov. 2015
*
Jeopardy game by Mary Pearson (JMU senior, Music Education), November 2015
* Twitter page1
(Live from Mars!) by
Kyle Schroeder (JMU junior, Sports & Management), Nov. 2015
* Twitter page2
(Eintein on Gravitational Waves) by
Rachel DiCerbo (JMU senior, Health Sciences), April 2016
* A Puzzle on Confirming Einstein's Theory through detection of
Gravitational Waves, by Meghan Mills (JMU senior, Economics), April 2016
*
Astronomy Rap (2 songs), by Christian Chenault (JMU sophomore, Computer
Science) and Nicalina Marciante (JMU junior, Marketing & Political
Science), April 2016
*
A Comic Strip on Pluto, by Kayla Byrnes (JMU sophomore, Graphic Design
- Book Arts), April 2016
* Basic
StoryTelling game made with Golang that describes exo-planet
exploration, by Pavan Gudimetta (JMU junior, Computer Science), April 2016
*
Find That Star, by Richard McGown (JMU junior, Computer
Science), April 2016
*
Alice in Trappist-1 Land , an adaptation of Alice in Wonderland
by Lewis Carroll (skit/video) by Rebecca Klein & Rachel Kimberlin
(JMU juniors, School of Theatre and Dance), April 2017 (see here for the script)
*
Expanding Universes , rap song by Dylan Vega
(JMU junior, Media Arts and Design/Music Industry), April 2017 ( here are the lyrics)
*
A Musk-y Initiative , a hilarious skit about space travel, by
Logan Allen Brown & Diego F. Salinas (JMU seniors, School of Theatre
and Dance), April 2017 (see here for the script)
* An Astronomy Grudge Match: Two Stars Go at
It; a wrestling match between a red giant
and a failed star (i.e., a brown dwarf) who are orbitting one
another, ripping and stripping of gas, giving birth to a white
dwarf, etc.; by Rob Condas (JMU senior, School of Theatre
and Dance), Nov. 2017
* A
crossword puzzle about the gravitational wave detection from
colliding black holes, by Sharmin Akter (JMU senior, accounting major); Nov. 2017
*
Falling Straight Into You , a little parody song about the Cassini
descent into Saturn, by Lindsey Bross and Katie Carbone
(JMU junior; Music Education Major - Voice), Nov. 2017
My
contributions
to JMU as a
scientist and
educator are
amplified by
my voice in
linking these
worlds with
servicing both
the campus and
beyond JMU. My
presence and
career advice
are constantly
sought after
in the
community, and
I respond with
great
enthusiasm to
invi- tations
to public
talks,
discussions,
and mentoring
opportunities
for middle and
high schools,
and
particularly
for
organizations
that help and
promote
scientific
literacy to
marginalized
populations. I
have founded,
led,
developed, or
organized
within and
around JMU
multiple
successful
outreach
programs like
Astronomy at
the Market, an
energetic and
immensely successful
grass-roots
outreach
program that
took Astronomy
to the market,
literally,
offering large
crowds of
people the
chance to meet
with astrophysicists and discuss science. With
Demystifying the Expert, I have invited the JMU student-led improvisational comedy troupe to delight audiences through interactions with our expert science faculty, as the main tool to unlock, decipher, and enjoy the mystery of the scientific research. The program gets everyone in with lots of laughs, at no expense to academic quality, community involvement, diversity, excellence, integrity, and student focus.
Thanks to my highly engaged nature, as well as to my
expertise in the field, I was selected as a AAS member to participate in March 2019 to
meetings with congressional representatives on Capitol Hill, to
advocate for community-derived priorities provided in the National Academies decadal surveys, as well as the value of the astronomical sciences as part of a strong U.S. portfolio of discovery research. I have used these meetings to emphasize the crucial need for augmentation of the astrophysics research grants and for enhancements to current and planned astronomical observing facilities, as well as to make known the uniquely fruitful research efforts conducted here at JMU with our undergraduate students, which would be impossible without a healthy financial federal support.
Research
Group Members
Christian Orrico ;
Summer 2024 - present; Physics Major
- project: The Structure Function of Mid-Infrared Variability
in Galaxies with and without Water Megamaser Emission
* 2024 Summer
Research Symposium, @JMU (poster)
Gaudeor Rudmin ;
Summer 2023 - 2024; Enginering Major
- project: Linking Near-IR Coronal Line Emission and Void/Wall
Environmental Properties with Water Megamaser Emission
* 2023 JMU
Summer Research Symposium (talk)
My research students have often been featured on JMU’s front
webpage stories (e.g.,
here and here),
on Madison
Magazine, or The
Breeze, where my mentoring efforts are recognized as “putting
JMU students in the thick of historic discovery,” or as offering
unprecedented opportunities for my students to “find out what’s at
the end of the universe.”
Will St. John ;
Spring 2021 - Summer 2022; Massanutten Regional Governor's School
- project: Quantifying the Nuclear Optical Spectral
Variability of Host Galaxies of Water Maser Disks
* Massanutten Regional Governor’s School Research Project Symposium, December 2021
* Grand
Prize Winner at 2022 Shenandoah Valley Regional Science & Engineering
Fair (@JMU) * Virginia State Science and Engineering Fair, virtual talk, April 2022
* Rockingham County Public School Board, virtual talk, April 2021
* International Science and Engineering Fair; virtual talk, May 2022
Riley Hazan; Summer 2021; physics major
- project: The Hard X-ray -- Mid Infrared Luminosity relation for maser
and nonmaser galaxies
Cameron Kelahan ;
Spring, Summer 2020+; computer-science major
- project: Machine Learning applications to efficient
searches for Water Maser Disks
*
238th AAS Meeting, June 2021 (iPoster)
Rebecca Burton ;
Summer 2019; Pre-Major in Physics
- project: Where do the Host Galaxies of Water Maser Disks
Lie on the Fundamental Plane of Black Hole Activity?
* 2019 JMU Summer Research
Symposium (poster)
Jacob Green ; Fall
2015 -- 2016; physics major
- project: Monte-Carlo simulations of Active Galactic Nuclei
optical spectra and decade scale variablity in their Broad
Line Region
* 2016 PandA Research
Symposium (talk) * poster presentation at the 13th CAA Undergraduate Research
Conference, The College of William and Mary, April 2016.
Chris Castillo ; Spring
2014 -- 2015; physics major
- project: spectral analysis, detection and measurements of the
broad line region in Hubble Space Telescope - Space Telescope Imaging Spectrograph (STIS) spectra of nearby
galaxy nuclei.
* Constantin et
al. (incl. Castillo), in The Astrophysical
Journal, arxiv:1509.04297
Nathan DiDomenico; Summer
2010 -- Spring 2013; physics major
- project: database mining; cross-matching surveys; identifying
and understanding the optical properties of megamasers' host
galaxies; developing, testing and implementing Principal Ccomponent
Analysis software.
* 2011 PandA Research
Symposium (movie)
= second best presentation!
* poster
at the 78th Annual Meeting of the Southeast Section of the APS,
October 2011
* 2012 REU Research
Symposium, JMU (talk slides)
Jamil Guevara; Summer
2012; physics major
- project: optical spectroscopy of galaxy nuclei; spectral
fitting, preparing datasets for new ground-based observations; data mining.
Thomas Redpath; Summer & Fall
2011; physics major
- project: SDSS database mining; investigating the large and small scale
environment of maser galaxies via near-neighbor statistics
* poster
at the 78th Annual Meeting of the Southeast Section of the APS,
October 2011
* refereed
journal paper in the Colonial Academic Alliance Undergraduate
Research Journal, 2012: "A Near-Neighbor Statistical Survey of the
Environments of Galaxies with Water Masers," with Nathan DiDomenico
and James Corcoran.
Anthony Miles; Spring 2011; computer-science major
- project: X-ray analysis of Chandra data; udnerstanding the
X-ray morphology of X-ray Bright Optically Normal Galaxies
(or... XBONGs)
* 2011 PandA Research
Symposium (movie)
Scott Fix, Research Assistant, 2009-2010
(JMU physics graduate, 2007)
- project: Nebular optical emission in nearby galaxy
nuclei. Optical spectroscopy.
* 2010 PandA Research Symposium
Greg Minutillo; Spring+Summer
2010; biology major
project: morphological classification of Chandra detected SDSS galaxies
* 2010 PandA Research Symposium
Brittney Byars; 2009-2010; physics major
- project: properties of obscuring dust in quasars; HST
spectroscopic data analysis
* 2010 PandA Research Symposium
Laura Simone; 2009-2010; physics major
- project: structure of obscuring dust in quasars
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