Montage used in the generation of the STARBIRDS Archive

McQuinn, Mitchell and Skillman (2015) recently published “The Panchromatic STARBurst IRregular Dwarf Survey (STARBIRDS): Observations and Data Archive.” They combined new and archival multi-wavelength observations for 20 nearby starburst and post-starburst dwarf galaxies to create a new archive of calibrated, homogeneously reduced images: the  “STARBurst IRregular Dwarf Survey” archive. They aggregated   images from the Galaxy Evolution Explorer Telescope (GALEX), the Hubble Space Telescope (HST), and the Spitzer Space Telescope (Spitzer) Multiband Imaging Photometer instrument. The data sets include flux calibrated, background subtracted images, al co-registered to the same world coordinate system.

The team used the Montage module mJPEG to create grayscale preview JPEG files of all the FITS files – you can see some examples below.  The JPEGs were made using a Gaussian stretch of the full range of the original image up to a maximum flux level of 99.999% of all pixel values. One of the benefits of the Montage toolkit design is that components such as mJPEG can be included in a script or program for bulk creation of images.

Visit the archive at http://groups.physics.umn.edu/starburst-dwarf/_galaxy_sample.php.

Here are some sample images:

2015-08-07_16-27-29

 

 

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Montage Supports the Kepler Follow-Up Observation Program.

The Kepler Community Follow-up Program, known also as the Kepler Follow-up Observation Program and KFOP, is a program instituted to conduct follow-up observations on Kepler Objects of Interest (KOI), or signals observed by the Kepler spacecraft that may indicate the presence of a planet transiting its host star. Because  the transit method of finding planets tends to produce a large number of false positives, KFOP is intended to rule out false positives amongst the KOIs and confirm more discoveries of exoplanets.

The NASA Exoplanet Archive, in support of the KFOP, has utilized Montage to generate a finding chart and nearby source catalog for all of the Kepler planetary candidate systems.  The UKIRT Observatory had performed a J-band survey of the Kepler Field and generated a source detection catalog; there are 1100+ individual images with 16 million sources in the survey.  Montage was used to index the images and the catalog (using an R-tree indexing scheme) to enable rapid determination of the best image for each Kepler target and to create a list of sources within 30″ of the Kepler targets.  Montage was then used to orient all of the best images and generate 1 arcmin cutout images with jpeg previews, overlayed with an equatorial coordinate grid: an example is shown below.

The modular design of Montage enabled the processing to be run within IDL and further analyzed, all within a scripted environment.  The usefulness of the UKIRT to the Kepler Project and the Follow-Up program was greatly enhanced by the UKIRT products, and those products were easily generated and made available to the team through Montage.

 

4Ic-dc20140206UKJ

This blogpost was based on material provided to me by Dr. David Ciardi.

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The AKARI Far-Infrared All-Sky Survey Maps

Because Montage is designed is a toolkit of components written in ANSI-C,  projects may integrate the tools into their pipelines and processing environments to create new data products and perform science analysis.

The Japanese AKARI mission has used Montage to support the creation of far-infrared, all-sky (>99% coverage) survey maps at 65 μm, 90 μm, 140 μm, and 160 μm ,with spatial resolutions ranging from 1 to 1.5 arcmin.  The production of these maps in described in Doi et al. (2015).  These maps represent the first public release of the all-sky data. According to the authors, the AKARI survey ” reveals the large-scale distribution of ISM with the great detail… The AKARI FIR images are a new powerful resource from which to investigate the detailed nature of ISM from small scales to the full sky.”

Full sky AKARI maps at 65 μm, 90 μm, 140 μm, and 160 μm. Montage was used to support the creation of these maps.

Full sky AKARI maps at 65 μm, 90 μm, 140 μm, and 160 μm. Montage was used to support the creation of these maps.

 

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Montage Mosaics The Pillars Of Creation!

The Pillars of Creation in the Eagle Nebula (M16) remain one of the iconic images of the Hubble Space Telescope. Three pillars rise from a molecular cloud into an enormous HII region, powered by the massive young cluster NGC 6611. Such pillars are common in regions of massive star formation, where they form as a result of ionization and stellar winds.

In a paper that will shortly be published in MNRAS,  entitled “The Pillars of Creation revisited with MUSE: gas kinematics and high-mass stellar feedback traced by optical spectroscopy,” McLeod et al (2015)  analyze of new data acquired with the Multi Unit Spectroscopy Explorer (MUSE) instrument on the VLT.  They used Montage to create integrated line maps of the single pointings obtained at the telescope. The figure below shows an example of these maps:2015-04-30_15-35-49

The authors confirmed  the pillar tips are being ionized and photo-evaporated by the massive members of NGC 6611.  They found a new  bipolar outflow at the tip of the middle pillar and proposed that an embedded protostar is driving it. With the physical parameters and ionic abundances derived from the spectroscopic study, they estimated a mass loss rate due to photo-evaporation of 70 M⊙/Myr, which implies that these structures can expect to have a lifetime of 3 Myr.

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Relicensing the Montage Mosaic Engine to a BSD 3-Clause License.

t the AAS meeting in January, I gave a presentation at a Special Session on Software Licenses about how and why we relicensed Montage from a proprietary license to a more permissive BSD 3-clause.  You can see the short presentation below, and read the full text of the session here.

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The Kid Is Back: The Next Generation of the Montage Image Mosaic Engine

I am delighted to say that we have received funding from the National Science Foundation (NSF) to deliver the next generation of the Montage Image Mosaic Engine. This new effort responds to the dramatic evolution in the computational landscape astronomy in the past few years.  We will deliver, over the next two years:

  • Support for data cubes.
  • Support for two sky partitioning schemes, the Hierarchical Equal Area isoLatitude Pixelization (HEALPix), standard in cosmic background experiments; and the Tessellated Octahedral Adaptive Subdivision Transform (TOAST), used in immersive platforms such as the World Wide Telescope.
  • A set of turnkey tools and associated tutorial  that will enable astronomers who are not expert in distributed platforms and technologies to launch and manage processing at scale.
  • A library that will allow Montage to be run directly from languages such as Python.

Montage has recently been relicensed, and is now available under a BSD 3-clause license. We will be making the code available on GitHub.  We will also overhaul the web page and revive the Montage blog (here!).

The project staff are: Bruce Berriman (PI), John Good (Architect), Marcy Harbut (Documentation), Tom Robitaille and Ewa Deelman (collaborators). We are guided by a Users’ Panel consisting of Adam Ginsburg, August Muench and Suzanne Jacoby.

Just to whet your appetite, we show  a short video that displays the structure of a molecular disk wind in HD 163296, measured by ALMA (PI: M. Rawlings). The video shows a re-projection by Montage of a data cube of the star that covers multiple velocities relative to the center of the CO J=3-2 line.

And here is a poster that describes some of the features we will be delivering, presented at the 2015 NSF SI2 PI Workshop, February 15 and 16 2015 in Arlington, VA.

Montage-SI2-PI-Meeting-2015-Feb-11-fixed

PDF version:

Montage-SI2-PI-Meeting-2015-Feb-11-fixed

 

 

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Montage Used To Study The Structure of the Star-forming Cluster RCW 38

E. Winston et al. (2011) report that they used  Montage in their recent paper “The Structure of the Star-forming Cluster RCW 38.” This was a multiwavelength investigation that used Spitzer, Chandra and 2MASS data that probed the spatial distribution of the young stellar population in this high mass star-formation region.

The RCW 38 region observed with IRAC on Spitzer. The plot shows a three-band false color image of the cluster, where the mosaic at each wavelength was created from the four epochs of data combined using the Montage mosaicing software. The field shows the overlap region of the four IRAC bands. Blue is 3.6μm, green is 4.5μm, and red is 8.0μm. The reddish hue at 8.0μm is due mainly to diffuse PAH emission. Emission from shocked hydrogen is visible in green. The outline of the Chandra ACIS-I field of view is overlaid as a white square.

"The RCW 38 region observed with IRAC on Spitzer. The plot shows a three-band false color image of the cluster, where the mosaic at each wavelength was created from the four epochs of data combined using the Montage mosaicing software. The field shows the overlap region of the four IRAC bands. Blue is 3.6μm, green is 4.5μm, and red is 8.0μm. The reddish hue at 8.0μm is due mainly to diffuse PAH emission. Emission from shocked hydrogen is visible in green. The outline of the Chandra ACIS-I field of view is overlaid as a white square." From Winston et al (2011)

They found: “..624 YSOs: 23 class 0/I and 90 flat spectrum protostars, 437 Class II stars, and 74 Class III stars. We also identify 29 (27 new) O star candidates over the IRAC field. Seventy-two stars exhibit IR-variability, including seven class 0/I and 12 flat spectrum YSOs. A further 177 tentative candidates are identified by their location in the IRAC [3.6] vs. [3.6]-[5.8] cmd. We find strong evidence of subclustering in the region. Three subclusters were identified surrounding the central cluster, with massive and variable stars in each subcluster. The central region shows evidence of distinct spatial distributions of the protostars and pre-main sequence stars. A previously detected IR cluster, DB2001 Obj36, has been established as a subcluster of RCW 38. This suggests that star formation in RCW 38 occurs over a more extended area than previously thought. The gas to dust ratio is examined using the X-ray derived hydrogen column density, NH and the K-band extinction, and found to be consistent with the diffuse ISM, in contrast with Serpens & NGC1333. We posit that the high photoionising flux of massive stars in RCW 38 affects the agglomeration of the dust grains.”

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