• ## Publications from 2016

I haven't updated the 'publications' subdirectory for a long time, mostly because I forgot it existed. I'd like to go through these and update them with highlight figures etc, but there's no guarantee I'll find the time... this is really the kind of thing that should be done as the papers are submitted. But that checklist has been getting very long lately.

Immer2016a
Temperature structures in Galactic center clouds. Direct evidence for gas heating via turbulence

\aap  595  A94  (2016)

Galametz2016a
Water, methanol and dense gas tracers in the local ULIRG Arp 220: results from the new SEPIA Band 5 Science Verification campaign

\mnras  462  L36-L40  (2016)

Ginsburg2016b
Toward gas exhaustion in the W51 high-mass protoclusters

\aap  595  A27  (2016)

Battersby2016a
A Brief Update on the CMZoom Survey

(2016)

Lin2016a
Cloud Structure of Galactic OB Cluster-forming Regions from Combining Ground- and Space-based Bolometric Observations

\apj  828  32  (2016)

Eisner2016a
Protoplanetary Disks in the Orion OMC1 Region Imaged with ALMA

\apj  826  16  (2016)

McLeod2016b
Connecting the dots: a correlation between ionising radiation and cloud mass-loss rate traced by optical integral field spectroscopy

ArXiv e-prints      (2016)

Youngblood2016b
The Orion Fingers: Near-IR Spectral Imaging of an Explosive Outflow

\aj  151  173  (2016)

Svoboda2016a
The Bolocam Galactic Plane Survey. XIV. Physical Properties of Massive Starless and Star-forming Clumps

\apj  822  59  (2016)

Henshaw2016a
Molecular gas kinematics within the central 250 pc of the Milky Way

\mnras  457  2675-2702  (2016)

Robitaille2016a
Python in Astronomy 2016 Unproceedings

35  (2016)

McLeod2016a
A nebular analysis of the central Orion nebula with MUSE

\mnras  455  4057-4086  (2016)

Ginsburg2016a
Dense gas in the Galactic central molecular zone is warm and heated by turbulence

\aap  586  A50  (2016)

Ginsburg2016
CAMELOT: the Cloud Archive for MEtadata, Library & Online Toolkit

(2016)

Goddi2016a
Hot ammonia around young O-type stars. III. High-mass star formation and hot core activity in W51~Main

(2016)

Longmore2016a
Using young massive star clusters to understand star formation and feedback in high-redshift-like environments

(2016)

• ## Publications from 2014

Summary of publications from 2014 (just c&p'd from my bibdesk):

Bally2014b
Outflows, Dusty Cores, and a Burst of Star Formation in the North America and Pelican Nebulae

\aj  148  120  (2014)

Bally2014a
Absorption Filaments toward the Massive Clump G0.253+0.016

\apj  795  28  (2014)

Ginsburg2014a
The dense gas mass fraction in the W51 cloud and its protoclusters

(2014)

Battersby2014b
The Onset of Massive Star Formation: The Evolution of Temperature and Density Structure in an Infrared Dark Cloud

\apj  787  113  (2014)

Battersby2014a
The Comparison of Physical Properties Derived from Gas and Dust in a Massive Star-forming Region

\apj  786  116  (2014)

• ## Publications from 2015

Summary of publications from 2015 (just c&p'd from my bibdesk):

Ginsburg2015b
High-mass star-forming cloud G0.38+0.04 in the Galactic center dust ridge contains H$_2$CO and SiO masers

\aap  584  L7  (2015)

Colombo2015a
Graph-based interpretation of the molecular interstellar medium segmentation

\mnras  454  2067-2091  (2015)

Weilbacher2015a
A MUSE map of the central Orion Nebula (M 42)

\aap  582  A114  (2015)

Isella2015a
Next Generation Very Large Array Memo No. 6, Science Working Group 1: The Cradle of Life

(2015)

Colombo2015b
The road toward a full, high resolution Molecular Cloud catalog of the Galaxy

(2015)

Ginsburg2015c
Detecting Stars at the Galactic Centre via Synchrotron Emission

ArXiv e-prints      (2015)

Wang2015a
Large-scale filaments associated with Milky Way spiral arms

\mnras  450  4043-4049  (2015)

Bally2015a
The Orion fingers: Near-IR adaptive optics imaging of an explosive protostellar outflow

\aap  579  A130  (2015)

McLeod2015a
The Pillars of Creation revisited with MUSE: gas kinematics and high-mass stellar feedback traced by optical spectroscopy

\mnras  450  1057-1076  (2015)

Ellsworth-Bowers2015a
The Bolocam Galactic Plane Survey. XIII. Physical Properties and Mass Functions of Dense Molecular Cloud Structures

\apj  805  157  (2015)

Merello2015a
The Bolocam Galactic Plane Survey. XI. Temperatures and Substructure of Galactic Clumps Based On 350 $\mu$M Observations

\apjs  218  1  (2015)

Thompson2015c
The ionised,radical and molecular Milky Way: spectroscopic surveys with the SKA

Ellsworth-Bowers2015b
The Bolocam Galactic Plane Survey. XII. Distance Catalog Expansion Using Kinematic Isolation of Dense Molecular Cloud Structures with $^13$CO(1-0)

\apj  799  29  (2015)

Ginsburg2015a
The dense gas mass fraction in the W51 cloud and its protoclusters

\aap  573  A106  (2015)

• ## The Peculiar Balmer Decrement of SN 2009ip: Constraints on Circumstellar Geometry

SN2009ip is a particularly interesting "supernova" since it left a bright remnant behind, indicating that it was instead a supernova impostor.  The 2012B event, a brightening in late September 2012, looked like it might be a "genuine supernova", but maybe not.  Have a look at the other papers on this object: http://arxiv.org/abs/1210.3568http://arxiv.org/abs/1210.3347http://arxiv.org/abs/1209.6320. A few folks at CU, primarily Guy, had acquired some spectra of SN2009ip right around the 2012B event.  We had a quick look at the data and decided there was something really interesting in it that other groups (who probably had more complete data) had overlooked. The most interesting single point we noted was a peculiar "Balmer Decrement" (which is the ratio of H-alpha to H-beta).  The normal Balmer decrement is ~3 (2.87 at n~103 and 10000K), but we observed a decrement of ~1.4 (and so did others, see e.g. http://users.northnet.com.au/~bohlsen/Nova/sn2009ip.htm). This Balmer decrement is weird, because all normal effects will increase rather than decrease the Balmer decrement.

• Interstellar reddening - affects the blue more than the red, therefore should decrease H-beta relative to H-alpha.  Of course, the reddening towards SN2009ip has been measured to be quite low.
• Line Splitting due to optical depth in the H-beta line (photons become "trapped" in the n=4 state and "escape" via Paschen-alpha and H-alpha) - but this only serves to decrease H-beta and increase H-alpha.  This is known as "Case C recombination" (see Xu et al 1992, Figure 1)

So what can increase the Balmer decrement?  Two possibilities:

1. Hydrogen reaches local densities above 1013 cm-3: above these densities, it reaches collisional equilibrium with the gas and adopts the gas temperature.  At 10000K, H-beta will be a few times brighter than H-alpha [to-do: put exactly how much brighter...]
2. H-alpha becomes optically thick, while H-beta remains optically thin.  This is essentially a geometric argument, and is explored a little in the text.  If H-alpha becomes optically thick, more hydrogen won't increase the H-alpha brightness, but if H-beta remains optically thin, more hydrogen will increase its brightness.  Simple argument, and it hasn't been fully explored yet (does the radiative transfer work, or does the "Case-C" situation kick in too hard first?), but it is a plausible alternative.

If you want to see my calculations in action, check out the ipython notebook performing the calculations. In case you're interested in Case C recombination, here's a first step: a hydrogen level diagram with levels connected by the (sum of the) Einstein A values between the relevant levels (from http://physics.nist.gov/cgi-bin/ASD/lines1.pl, generated with https://github.com/keflavich/energyleveldiagrams).

• ## Galactic H2CO Densitometry I: Pilot survey of Ultracompact HII regions and methodology

First Author [ ADS ] [ Full Version ]

We examined 24 UCHII regions using the GBT to observe the 2-2 line of ortho-Formaldehyde. We measured the local gas density and compared to GMCs and other galaxies. We found densities in GMCs that are 1-2 orders of magnitude higher than the mean density in GMCs, implying that extreme overdensities are common even in "quiescent" (non-star-forming) GMCs. This work was almost entirely my own, but was seeded by Jeremy Darling Some highlight figures from the paper:

A sample spectrum. On the top, black is Formaldehyde 1-1, red is Formaldehyde 2-2. On the bottom, blue is 13CO, red is H77α, black is H110α.

Histograms of GMC mean densities and the densities measured directly from our survey. Note that even for "serendipitious" line of sight GMCs, the densities are MUCH higher than typical GMC densities.

Comparison of the measured column densities of formaldehyde and inferred number densities of H2.

• ## Characterizing Precursors to Stellar Clusters with Herschel

[ ADS ] [ arXiv ]

C. Battersby, J. Bally, A. Ginsburg, J.-P. Bernard, C. Brunt, G.A. Fuller, P. Martin, S. Molinari, J. Mottram, N. Peretto, L. Testi, M.A. Thompson 2011

The paper includes a careful characterization of the properties of both dense and diffuse regions within the two Hi-Gal Science Demonstration Phase fields (l=30 and l=59). It demonstrated that star formation tracers are more common at higher temperatures, and that IRDCs exist on both the near and far side of the galaxy, where the difference between near and far is around 5-7 kpc.

I helped develop the iterative background subtraction method and contributed to the discussion and conclusions; most of the work was Cara's but my experience with iterative flux estimation from the BGPS pipeline proved useful.

• ## The optically bright post-AGB population of the LMC

E. van Aarle, H. Van Winckel, T. Lloyd Evans, T. Ueta, P. R. Wood, and A. G. Ginsburg

A catalog of post-AGB stars in the LMC, useful in particular because they are at a common distance. Post-AGB stars are quite luminous (> 1000 LO usually), so easily detected in the LMC.

My contribution to this work was years ago; I worked on the SAGE project for a few months at the University of Denver with Toshiya Ueta. I generated a catalog of post-AGB objects and an online catalog with automatic SED plotter. It was a pretty neat project, but I left before I was able to convince others that my catalog was definitive; nonetheless it was eventually used in this publication. As an aside, that was my first foray into data languages, and I ended up using the Perl Data Language long before I learned of python and before I got a free IDL license.

• ## Star-forming Region Sh 2-233IR. I. Deep Near-infrared Observations toward the Embedded Stellar Clusters

[ ADS ] [ arXiv ]

My contributions to this paper were minor. Analysis of luminosity functions in the IRAS 05358+3543 region have identified different aged groups. The paper contributes to the picture of sequential (triggered?) star formation in the S233-235 region in Auriga.

• ## Outflows and Massive Stars in the protocluster IRAS 05358+3543

First Author [ ADS ] [ arXiv ]

A mm and near-IR study of the IRAS 05358+3543 system. Recently (2011), it has become clear that "protocluster" is unlikely to be the right label for IRAS 05358+3543. "proto-association" might be more accurate. Perhaps the most interesting result of this paper is the discovery that the central source is likely to be a 400-AU binary with two massive (>8 msun) stars at different evolutionary stages. It is just barely in ALMA's range...

• ## An Infrared Through Radio Study of the Properties and Evolution of IRDC Clumps

ADS arXiv I assisted in many of the technical aspects of the paper including Bolocam and VLA data reduction. We identify a potential evolutionary sequence among millimeter "clumps". HCO+ and N2H+ maps are used to measure the physical properties of some of these clumps.

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