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Jay Cross
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Attended Rensselaer Polytechnic Institute
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Astronomy Papers That Caught Fred's Eye In Today's arXiv
 
There are fifty-nine new papers accepted into Astro-Archives today.

"Eye-catching topics selected for this short summary include: Solar Flares, AGN, Core-Collapse events

A tiny event producing an interplanetary type III burst http://arxiv.org/abs/1507.08423 Remember the death ray used by the little space dude in Bugs Bunny cartoons? Apparently our own sun has secrets packed in the tiniest of flares, which can erupt as powerful ionized flashes elsewhere.

Active Galactic Nuclei Discovered in the Kepler Mission http://arxiv.org/abs/1507.08312 As a scientific object; the careful study of fluctuations in more than 500 active galactic is a complete success. Discovering what theses fluctuations can mean, and how to constrain them could take decades to sort-out.

An Integral Condition for Core-Collapse Supernova Explosions http://arxiv.org/abs/1507.08314 Core collapse supernova explosions are thought to begin when very massive stars run out of central fuel and collapse gravimetrically, ignited a heavily fueled nuclear sequence. But sometimes a core-collapse leads to a supernova, and other times the bouncing shock wave yields a highly compact neutron star rather than a massive explosive engine. These authors look at how subtle changes in initial conditions may lead to very different results.
Abstract: We investigate the conditions under which small scale energy release events in the low corona gave rise to strong interplanetary (IP) type III bursts. We analyze observations of three tiny events, detected by the Nan\c cay Radio Heliograph (NRH), two of which produced IP type IIIs.
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Astronomy Papers That Caught My Eye In Today's arXiv

There are 66 papers today (Wednesday), not counting replacements. 

Topics: Anisotropic Acceleration, 3 New MW Satellites, Real Time IceCube

Anisotropic Acceleration http://arxiv.org/abs/1507.07560 The universe is expanding, and the expansion is accelerating (slowly). We are now getting enough Type 1a supernova data that we can start to test to see if there is any unevenness in the rate of acceleration. (Future projects like EUCLID will do a better job). This study finds that there is a dipole in the acceleration that maps to the CMB dipole. The confidence level is not high enough to declare it a fact, but it is worth keeping in mind when modeling the universe.

3 New MW Satellites http://arxiv.org/abs/1507.07564 Years ago there was an issue that computer models of the LCDM universe produced more satellite dwarf galaxies than we see. In the time since then more have been discovered. Here are three more. They are hard to see because they are dim, but they are not far away.

Real Time IceCube http://arxiv.org/abs/1507.07871 IceCube is detecting high energy neutrinos, and is looking for them above the threshold where atmospheric interactions with cosmic rays drown out the signal. Up till now, it has taken a long time for information about when these events occur, which has been a problem for getting any kind of optical identification of the sources. Now the team running IceCube is getting ready to publish these event in near real time. Hopefully something UV, X-Ray, Optical, or Gamma sources will be found in the next few years.
Abstract: We present a method to test the isotropy of the magnitude-redshift relation of Type Ia Supernovae (SNe Ia) and single out the most discrepant direction (in terms of the signal-to-noise ratio) with respect to the all-sky data. Our technique accounts for possible directional variations ...
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Astronomy Papers That Caught Fred's Eye In Today's arXiv
 
Forty-one new papers have been accepted in Astro-archives today. Eye-catching topics included: Tycho's progenitor, New missions (FRRSPEX), Core-collapse supernova (type II) progenitors.

Newly Determined Explosion Center of Tycho's Supernova and the Implications for Proposed Ex-Companion Stars of the Progenitor http://arxiv.org/abs/1507.06347 Supernova type Ia are the best indicators we have of cosmic distances. But we really need to know whether this family of events involve single White dwarf stars, pairs of white dwarfs, or both. Tyco's Nova of 1542 is the most recent type Ia supernova event in our own galaxy, and our best shot at finding a supernova remnant star. But first things first; we must isolate the epicenter of an event before we can reasonable locate the remnant. This paper concludes the most recent searches have been off by a country mile, so to speak.

The Far-InfraRed Spectroscopic Explorer (FIRSPEX) http://arxiv.org/abs/1507.06458 Much of the stellar research of the 21st century will involve Infrared and far-infrared detection bandwidths of very distant galaxies. This proposed mission will focus on IR and Far-IR sources in our own galaxies; which in turn will help identify local contaminates in more distant galaxy searches.

The disappearance of the progenitor of SN 2012aw in late-time imaging http://arxiv.org/abs/1507.06579 The progenitors of core-collapse supernova events are thought to be large red giants, massive stars that run out of hydrogen fuel and collapse upon themselves before exploding virtually every ounce of nuclear fuel. If this is true, the progenitor to supernova 2012aw should no longer exist...and apparently, it does not.

Dust in the Local Group http://arxiv.org/abs/1507.06604 (A review article).
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Astronomy Papers That Caught My Eye In Today's arXiv

There are 59 papers today (Wednesday), not counting replacements. 

Topics: Not From Dark Matter, SMF at 4<z<8, No Supernova

Not From Dark Matter http://arxiv.org/abs/1507.05616 There is an excess of gamma rays coming from near the galactic center. Some models predict that self-annihilating dark matter should be very concentrated near the galactic center and be giving off such gamma rays. This team looks at the possibility that these gammas are coming from millisecond pulsars that formed in globular clusters, and were released into the central bulge as the clusters were disrupted. The spectral signature was predicted without any free parameters, and the observations match very closely to those predictions.

GSMFs at 4<z<8 http://arxiv.org/abs/1507.05636  Galaxy Stellar Mass Functions (GSMFs) is one measure being examined to see changes in galaxy evolution in  earlier days of the universe. This team examined 4500 galaxies found in the Hubble UDF and the Spitzer CANDELS surveys, to examine this feature, and through this, we get a look at the stellar mass density of the stars in galaxies during this interesting period, and see that the high end of mass grew over time, but the low end did not. This means that there is some process for differential growth depending on initial mass of the galaxies, and this paper shows when that differentiation was taking place.

No Supernova http://arxiv.org/abs/1507.05823 If a star is big enough, it might be able to collapse into a black hole with so modest an explosion that we wouldn't notice it. Could this really happen? This team went through Hubble images from 1994 and 2013 looking for missing giant stars in fifteen nearby galaxies... and found one (maybe). One yellow supergiant (similar to Rho Cas) with a mass of 25-30 solar masses was there in 1994, and not there in 2013, in galaxy NGC3021. If this happened then future deeper surveys with bigger telescopes should start detecting these events with greater frequency.
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Astronomy Papers That Caught My Eye In Today's arXiv

There are 74 papers today (Tuesday), not counting replacements. Note that a large fraction of these are about the Dark Energy Survey.

Topics: Video for Occultations, Two New Neptune Trojans, Geoengineering Ice Caps

Video for Occultations http://arxiv.org/abs/1507.05151 Are you an amateur astronomer interested in transient phenomena? It is hard to get an image-record of something that changes quickly, such as occultations. It would be interesting to observe stars as KBOs pass in front of them, and look for signs of atmosphere, rings, or satellites. This paper looks at a $4500 CCD video camera from Point Grey, and looks at its merits for this sort of task, including what are the limits of what it can see at 30 frames per second. 

Two New Neptune Trojans http://arxiv.org/abs/1507.05177 The L4 Lagrange Point for Neptune is 1/6th of an orbit ahead of Neptune, and two new asteroids have been found there (there are already seven other known asteroids there, plus two at L5). This discovery is not so much Earth-shaking as it is an interesting side discovery for the Dark Energy Survey. Teams connected to DES have released ten papers today, and while most of them are about the search for supernovae, and the understanding of factors such as lensing affecting their brightness, or the equipment, this paper was a result of identifying what would otherwise be considered noise.

Geoengineering Ice Caps http://arxiv.org/abs/1507.05495 The ice caps are melting, and our coastal cities and island nations are threatened by rising sea level. This paper looks at a (slow) way to increase the size of the polar ice caps and make the planet more stable against certain climate threats. Note that it will take thousands of years of expensive effort to do this, so this is not a short term solution.
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Astronomy Papers That Caught My Eye In Today's arXiv

There are 52 papers today (Monday), not counting replacements.

Topics: Astro-H & 3.5 keV, Giant Crab Pulses, Anti-matter Galaxies

Astro-H & 3.5 keV http://arxiv.org/abs/1507.04744 There has been a lot of buzz in the last year or so about the 3.5 keV soft x-ray lines coming from galaxy centers as a possible indicator of Dark Matter. It is hard to tell much about this so far because of the lack of precision spectra available so far, but the Astro-H mission (soon to be launched) should have the tools to do the job, and help confirm or rule out dark matter annihilation as a source.

Giant Crab Pulses http://arxiv.org/abs/1507.04830 Every once in a while there are giant pulses from the Crab Nebula Pulsar. What causes them? There are some models, but they don't all agree. This paper looks at simultaneous observations of these pulses at several radio ranges observed with Parkes and Murchison, with hopes of narrowing the models that describe the emission mechanism.

Anti-matter Galaxies http://arxiv.org/abs/1507.04887 Could there be large regions of space made of antimatter? I think the lack of anti-Iron nuclei in the cosmic rays says no, but this paper takes a closer look at what we would see if there were any such regions in the observable universe.
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There's also a good proposal paper about the need for the High Definition Space Telescope (HDST) to eventually replace the Hubble Space Telescope.
The proposal is for a 12 meter optical/UV space telescope that will sit out at the L2 Lagrange point to find and characterize Earth-like planets, and make fundamental advances across virtually all fields of astronomy and astrophysics.
This paper doesn't detail specifics of design or construction, but is more of a general synopsis of what this kind of instrument could do.
http://arxiv.org/abs/1507.04779
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Astronomy Papers That Caught Fred's Eye In Today's arXiv
 
There are fifty new papers published in Astro-archives today. Eye-catch topics selected include: Solar Activity/Cosmic Ray anti-correlation, Quasar environments, Wide Field Radio telescopes results, Earth-sized exo-planets

Study of Cosmic-Ray Modulation during the Recent Unusual Minimum and Mini Maximum of Solar Cycle 24 http://arxiv.org/abs/1507.07917 The atmospheric cosmic ray detection rate increases during periods of solar minimum. This seems counter-intuitive, but it illustrates two things: 1) Solar activity is not the source of cosmic rays 2) The strengthening of the radiation belt during periods of solar activity actually helps protect us from cosmic rays. The paper also looks at the 'lag time' between when cosmic ray bombardments are high and solar activity is high.

Dissecting the complex environment of a distant quasar with MUSE http://arxiv.org/abs/1507.07919 Quasars activity appears to have peaked at redshift ~ 2, and then dwindles off both prior to and after this period which appears rich in Active Galactic nuclei (AGN). This paper looks very closely at an active system at a redshift distance of ~3.

Murchison Widefield Array Observations of Anomalous Variability: A Serendipitous Night-time Detection of Interplanetary Scintillation
http://arxiv.org/abs/1507.08236 the Murchison Widefield Array is a radio telescope that has just come on line, and what a discovery: A large patch of ejected solar plasma moving across the night sky! Now we have a new seeing mess to worry about!

Two Transiting Earth-size Planets Near Resonance Orbiting a Nearby Cool Star http://arxiv.org/abs/1507.08256 Most of the exoplanets found to-date are very large. So how cool is it that we found two near-earth-sized planets in the same M0 Dwarf solar system!
Abstract: After a prolonged and deep solar minimum at the end of Cycle 23, the current Solar Cycle 24 is one of the lowest cycles. These two periods of deep minimum and mini maximum are separated by a period of increasing solar activity. We study the cosmic-ray intensity variation in relation ...
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Human death is assured with today's technology, but we might be able to get a functioning machine to one of them.  (Not before all of us are dead, of course, but eventually.)

It would be hard to get excited about something whose results wouldn't be known for generations, however.  And there's a distinct possibility our descendants wouldn't be paying attention or wouldn't have the ability to decode the signals when they did come. :-/
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Astronomy  - 
 
Astronomy Papers That Caught My Eye In Today's arXiv

There are 66 papers today (Wednesday), not counting replacements. 

Topics: Anisotropic Acceleration, 3 New MW Satellites, Real Time IceCube

Anisotropic Acceleration http://arxiv.org/abs/1507.07560 The universe is expanding, and the expansion is accelerating (slowly). We are now getting enough Type 1a supernova data that we can start to test to see if there is any unevenness in the rate of acceleration. (Future projects like EUCLID will do a better job). This study finds that there is a dipole in the acceleration that maps to the CMB dipole. The confidence level is not high enough to declare it a fact, but it is worth keeping in mind when modeling the universe.

3 New MW Satellites http://arxiv.org/abs/1507.07564 Years ago there was an issue that computer models of the LCDM universe produced more satellite dwarf galaxies than we see. In the time since then more have been discovered. Here are three more. They are hard to see because they are dim, but they are not far away.

Real Time IceCube http://arxiv.org/abs/1507.07871 IceCube is detecting high energy neutrinos, and is looking for them above the threshold where atmospheric interactions with cosmic rays drown out the signal. Up till now, it has taken a long time for information about when these events occur, which has been a problem for getting any kind of optical identification of the sources. Now the team running IceCube is getting ready to publish these event in near real time. Hopefully something UV, X-Ray, Optical, or Gamma sources will be found in the next few years.
Abstract: We present a method to test the isotropy of the magnitude-redshift relation of Type Ia Supernovae (SNe Ia) and single out the most discrepant direction (in terms of the signal-to-noise ratio) with respect to the all-sky data. Our technique accounts for possible directional variations ...
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Astronomy Papers That Caught Fred's Eye In Today's arXiv
 
There are thirty-nine papers archived into Astro-archives today. These papers caught my eye:

Topics: Magnetar flares, Cosmic rays generated by supernova, the solar corona, The definition of a Planet, Dark Matter and scientific philosophy.


XMM-Newton observations of SGR 1806-20 over seven years following the 2004 Giant Flare http://arxiv.org/abs/1507.05985 When I was a kid, we used to break firecrackers in-half, but leaving one edge still hinged. Then carefully light both halves and the same time, which would launch the jetting firecracker into a spinning mode we called a 'dog and cat fight'. I never thought I would read a scientific paper about a magnetar doing the same thing, but then I never expected to read about a magnetar, either.

On the cosmic ray spectrum from type II Supernovae http://arxiv.org/abs/1507.06086 One of the great mysteries of the universe is how particles are accelerated to cosmic ray energies. This paper looks at one of the most promising mechanisms: Supernova type II explosions. They cannot find workable parameter sets, but not for lack of trying. Space may be hard, but cosmic rays are harder.

Kinetic Alfvén waves generation by large-scale phase-mixing http://arxiv.org/abs/1507.06233 Protons which have enough kinetic energy to escape from the boiling surface of the sun carry with them considerable baggage: a electric field that will interact with other protons also emerging from the surface. This paper makes a case from resonant properties in these fields elevating corona photons to the temperatures we observe.

The Duhem-Quine thesis and the dark matter problem http://arxiv.org/abs/1507.06282 This is a philosophical look at the Dark Matter problem; which includes as a bonus, a quick tutorial on the Bacon, Popper and Duhem facets of physical science.

A Quantitative Criterion for Defining Planets http://arxiv.org/abs/1507.06300 Since our visit to the rather terrestrial-looking planet Pluto, expect a few more papers like this to pop-up.

At What Distance Can the Human Eye Detect a Candle Flame? http://arxiv.org/abs/1507.06270 Fun paper by Kevin
Krisciunas and Don Carona; but I missed the part where they standardized the candle.
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Re: The Duhem-Quine thesis and the dark matter problem (specifically the 'demarcation problem')
https://plus.google.com/106045608115852817529/posts/3bwL3fkYb6u
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Jay Cross

Astronomy  - 
 
Astronomy Papers That Caught My Eye In Today's arXiv

There are 59 papers today (Wednesday), not counting replacements. 

Topics: Not From Dark Matter, SMF at 4<z<8, No Supernova

Not From Dark Matter http://arxiv.org/abs/1507.05616 There is an excess of gamma rays coming from near the galactic center. Some models predict that self-annihilating dark matter should be very concentrated near the galactic center and be giving off such gamma rays. This team looks at the possibility that these gammas are coming from millisecond pulsars that formed in globular clusters, and were released into the central bulge as the clusters were disrupted. The spectral signature was predicted without any free parameters, and the observations match very closely to those predictions.

GSMFs at 4<z<8 http://arxiv.org/abs/1507.05636  Galaxy Stellar Mass Functions (GSMFs) is one measure being examined to see changes in galaxy evolution in  earlier days of the universe. This team examined 4500 galaxies found in the Hubble UDF and the Spitzer CANDELS surveys, to examine this feature, and through this, we get a look at the stellar mass density of the stars in galaxies during this interesting period, and see that the high end of mass grew over time, but the low end did not. This means that there is some process for differential growth depending on initial mass of the galaxies, and this paper shows when that differentiation was taking place.

No Supernova http://arxiv.org/abs/1507.05823 If a star is big enough, it might be able to collapse into a black hole with so modest an explosion that we wouldn't notice it. Could this really happen? This team went through Hubble images from 1994 and 2013 looking for missing giant stars in fifteen nearby galaxies... and found one (maybe). One yellow supergiant (similar to Rho Cas) with a mass of 25-30 solar masses was there in 1994, and not there in 2013, in galaxy NGC3021. If this happened then future deeper surveys with bigger telescopes should start detecting these events with greater frequency.
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Astronomy  - 
 
Astronomy Papers That Caught My Eye In Today's arXiv

There are 74 papers today (Tuesday), not counting replacements. Note that a large fraction of these are about the Dark Energy Survey.

Topics: Video for Occultations, Two New Neptune Trojans, Geoengineering Ice Caps

Video for Occultations http://arxiv.org/abs/1507.05151 Are you an amateur astronomer interested in transient phenomena? It is hard to get an image-record of something that changes quickly, such as occultations. It would be interesting to observe stars as KBOs pass in front of them, and look for signs of atmosphere, rings, or satellites. This paper looks at a $4500 CCD video camera from Point Grey, and looks at its merits for this sort of task, including what are the limits of what it can see at 30 frames per second. 

Two New Neptune Trojans http://arxiv.org/abs/1507.05177 The L4 Lagrange Point for Neptune is 1/6th of an orbit ahead of Neptune, and two new asteroids have been found there (there are already seven other known asteroids there, plus two at L5). This discovery is not so much Earth-shaking as it is an interesting side discovery for the Dark Energy Survey. Teams connected to DES have released ten papers today, and while most of them are about the search for supernovae, and the understanding of factors such as lensing affecting their brightness, or the equipment, this paper was a result of identifying what would otherwise be considered noise.

Geoengineering Ice Caps http://arxiv.org/abs/1507.05495 The ice caps are melting, and our coastal cities and island nations are threatened by rising sea level. This paper looks at a (slow) way to increase the size of the polar ice caps and make the planet more stable against certain climate threats. Note that it will take thousands of years of expensive effort to do this, so this is not a short term solution.
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Jay Cross

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Astronomy Papers That Caught My Eye In Today's arXiv

There are 52 papers today (Monday), not counting replacements.

Topics: Astro-H & 3.5 keV, Giant Crab Pulses, Anti-matter Galaxies

Astro-H & 3.5 keV http://arxiv.org/abs/1507.04744 There has been a lot of buzz in the last year or so about the 3.5 keV soft x-ray lines coming from galaxy centers as a possible indicator of Dark Matter. It is hard to tell much about this so far because of the lack of precision spectra available so far, but the Astro-H mission (soon to be launched) should have the tools to do the job, and help confirm or rule out dark matter annihilation as a source.

Giant Crab Pulses http://arxiv.org/abs/1507.04830 Every once in a while there are giant pulses from the Crab Nebula Pulsar. What causes them? There are some models, but they don't all agree. This paper looks at simultaneous observations of these pulses at several radio ranges observed with Parkes and Murchison, with hopes of narrowing the models that describe the emission mechanism.

Anti-matter Galaxies http://arxiv.org/abs/1507.04887 Could there be large regions of space made of antimatter? I think the lack of anti-Iron nuclei in the cosmic rays says no, but this paper takes a closer look at what we would see if there were any such regions in the observable universe.
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