Milky Way

Astronomy Magazine Talks to the Team Who Discovered the Radcliffe Wave

December 1, 2020

Astronomy Magazine talks to the team from Harvard’s Radcliffe Institute for Advanced Study and Harvard-Smithsonian Center for Astrophysics (CfA) about their serendipitous discovery of the Radcliffe Wave, a massive interconnected stream of stellar nurseries, molecular clouds, and supernovae that snakes through the Milky Way galaxy - and how history, art and science came together to enable this paradigm-changing discovery.  Read the full article ...

Read more about Astronomy Magazine Talks to the Team Who Discovered the Radcliffe Wave
glue-ing Together the Universe, at Microsoft New England Research Division, Cambridge, MA , Friday, March 6, 2020:

Astronomers have a long history of visualization. Going back only as far as Galileo, discoveries were made using sketches of celestial objects moving over time. Today, Astronomy inquiries can, and often do, make use of petabytes of data at once. Huge surveys are analyzed statistically to understand tiny fluctuations that hint at the fundamental nature of the Universe, and myriad data sets, from telescopes across the globe and in space are brought together to solve problems ranging from the nature of black holes to the structure of the Milky Way to the origins of planets like Earth. In...

Read more about glue-ing Together the Universe
Pecan Pie Logo for "PRISEd Conversation 2020" with photo of Dr. Goodman

Blog Feature: Dr. Alyssa Goodman talks with the The Harvard College Program in Science and Engineering (PRISE)

September 23, 2020

Dr. Alyssa Goodman talks with Felicia Ho, PRISE, Harvard College '23 about Jacques Cousteau, data visualization, climate change, prediction science, and the wide arc of influences that have shaped her multifaceted career as the Robert Wheeler Wilson Professor of Applied Astronomy at Harvard. 


Read more about Blog Feature: Dr. Alyssa Goodman talks with the The Harvard College Program in Science and Engineering (PRISE)
Catherine Zucker, Joshua S. Speagle, Edward F. Schlafly, Gregory M. Green, Douglas P. Finkbeiner, Alyssa Goodman, and João Alves. 1/2020. “A Compendium of Distances to Molecular Clouds in the Star Formation Handbook.” Astronomy and Astrophysics, 633, Pp. A51.Abstract
Accurate distances to local molecular clouds are critical for understanding the star and planet formation process, yet distance measurements are often obtained inhomogeneously on a cloud-by-cloud basis. We have recently developed a method that combines stellar photometric data with Gaia DR2 parallax measurements in a Bayesian framework to infer the distances of nearby dust clouds to a typical accuracy of ∼5%. After refining the technique to target lower latitudes and incorporating deep optical data from DECam in the southern Galactic plane, we have derived a catalog of distances to molecular clouds in Reipurth (2008, Star Formation Handbook, Vols. I and II) which contains a large fraction of the molecular material in the solar neighborhood. Comparison with distances derived from maser parallax measurements towards the same clouds shows our method produces consistent distances with ≲10% scatter for clouds across our entire distance spectrum (150 pc-2.5 kpc). We hope this catalog of homogeneous distances will serve as a baseline for future work. Table A.1 is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr ( or via http://cdsarc.u-strasbg.fr/viz- bin/cat/J/A+A/633/A51. It is also available on the Harvard Dataverse at http://https://doi.org/1 0.7910/DVN/07L7YZ An interactive 3D version of Fig. 2 is available at http://https://www.aanda.org
P. Udomprasert, H. Houghton, S. Sunbury, J. Plummer, A. Goodman, and P. Sadler. 2020. “Best Practices in Astronomy Education: Long-Term Retention of Learning Gains with the WWT ThinkSpace Seasons Lab.” Conference Paper, 385, 07.Abstract

Seasons is a middle school science topic where students commonly hold strong misconceptions. Ideas about seasons are so resistant to change because the Earth-Sun system is a complex, dynamic system that requires strong spatial reasoning to fully understand. Most "traditional" methods of instruction (lecture, textbook diagrams, passively-watched videos) do not adequately support students in the spatial reasoning tasks needed to understand seasons. The ThinkSpace Seasons Lab specifically targets the necessary spatial reasoning skills and strategies (for example, connecting the position of the Sun in a space-based perspective with the position in the sky in an Earth-based perspective), by blending visualizations from the WorldWide Telescope program and hands-on models. Student understanding of seasons after using the ThinkSpace curriculum increases with large effect size, and we have longitudinal data showing that two years post-instruction, students who used the ThinkSpace curriculum have stronger recollection of key seasons concepts than peers who used "traditional" curricula.

A. Goodman, J. Alves, C. Zucker, J. S. Speagle, S. Meingast, T. Robitaille, D. P. Finkbeiner, E. P. Schlafly, and G. M. Green. 2020. “A New Feature of the Galaxy Revealed by 3D Dust Mapping.” Conference Paper, 385, 05.Abstract
We present a new, very large, highly-elongated, undulating, gaseous structure lying just beyond the current orbit of the Sun in the Milky Way. The structure was discovered using 3D-dust mapping techniques, and it encompasses several star-forming regions formerly associated with "Gould's Belt" and the "Local Arm" of the Galaxy. Gaia data, along with several other large surveys, were critical to this discovery. We will present several three-dimensional views for this new object, and speculate on its origins.
Che-Yu Chen, Erica A. Behrens, Jasmin E. Washington, Laura M. Fissel, Rachel K. Friesen, Zhi-Yun Li, Jaime E. Pineda, and et al. 2020. “Relative Alignment between Dense Molecular Cores and Ambient Magnetic Field: The Synergy of Numerical Models and Observations.” arXiv E-Prints.Abstract

The role played by magnetic field during star formation is an important topic in astrophysics. We investigate the correlation between the orientation of star-forming cores (as defined by the core major axes) and ambient magnetic field directions in 1) a 3D MHD simulation, 2) synthetic observations generated from the simulation at different viewing angles, and 3) observations of nearby molecular clouds. We find that the results on relative alignment between cores and background magnetic field in synthetic observations slightly disagree with those measured in fully 3D simulation data, which is partly because cores identified in projected 2D maps tend to coexist within filamentary structures, while 3D cores are generally more rounded. In addition, we examine the progression of magnetic field from pc- to core-scale in the simulation, which is consistent with the anisotropic core formation model that gas preferably flow along the magnetic field toward dense cores. When comparing the observed cores identified from the GBT Ammonia Survey (GAS) and Planck polarization-inferred magnetic field orientations, we find that the relative core-field alignment has a regional dependence among different clouds. More specifically, we find that dense cores in the Taurus molecular cloud tend to align perpendicular to the background magnetic field, while those in Perseus and Ophiuchus tend to have random (Perseus) or slightly parallel (Ophiuchus) orientations with respect to the field. We argue that this feature of relative core-field orientation could be used to probe the relative significance of the magnetic field within the cloud.

João Alves, Catherine Zucker, Alyssa A. Goodman, Joshua S. Speagle, Stefan Meingast, Thomas Robitaille, Douglas P. Finkbeiner, Edward F. Schlafly, and Gregory M. Green. 1/2020. “A Galactic-Scale Gas Wave in the Solar Neighbourhood.” Nature, 578, Pp. 237–239. Publisher's VersionAbstract
For the past 150 years, the prevailing view of the local interstellar medium has been based on a peculiarity known as the Gould Belt1-4, an expanding ring of young stars, gas and dust, tilted about 20 degrees to the Galactic plane. However, the physical relationship between local gas clouds has remained unknown because the accuracy in distance measurements to such clouds is of the same order as, or larger than, their sizes5-7. With the advent of large photometric surveys8 and the astrometric survey9, this situation has changed10. Here we reveal the three- dimensional structure of all local cloud complexes. We find a narrow and coherent 2.7-kiloparsec arrangement of dense gas in the solar neighbourhood that contains many of the clouds thought to be associated with the Gould Belt. This finding is inconsistent with the notion that these clouds are part of a ring, bringing the Gould Belt model into question. The structure comprises the majority of nearby star-forming regions, has an aspect ratio of about 1:20 and contains about three million solar masses of gas. Remarkably, this structure appears to be undulating, and its three-dimensional shape is well described by a damped sinusoidal wave on the plane of the Milky Way with an average period of about 2 kiloparsecs and a maximum amplitude of about 160 parsecs.
Photo of Milky Way

Professors Offer Insights From Their Fields Amid COVID

July 10, 2020

In this time of profound uncertainty, society can be sure of one thing: more uncertainty. The seemingly opaque path forward for us, individually and collectively, was the Gazette’s topic with three Harvard professors, including Robert Wheeler Willson Professor of Applied Astronomy, Dr. Alyssa Goodman, who shared insights into how uncertainty is viewed in their fields, and the surprising ways in which it’s not necessarily a bad thing. ...

Read more about Professors Offer Insights From Their Fields Amid COVID
Photo of Astronomer João Alves

Radcliffe Fellow Dr. João Alves On Discovering the "Radcliffe Wave"

June 30, 2020

Astronomer João Alves came to the Radcliffe Institute for Advanced Study to create a 3D map of the sky, but what he discovered overturned the common conception of how stars are born and compelled scientists to rethink the framework of the galaxy.

A professor of stellar astrophysics at the University of Vienna, Alves focuses on understanding how natural processes change large interplanetary clouds of gas into stars and planets, and ultimately form life. He chose to pursue his research at Radcliffe because of its creative, multidisciplinary approach to collaboration. ...

Read more about Radcliffe Fellow Dr. João Alves On Discovering the "Radcliffe Wave"