[Alumnos] Type Ia Supernova in M101; Keck Is Participating

Vie Ago 26 01:36:42 ART 2011

Hola a todos,

disculpen que reenvio directamente el mail en ingles, pero es viernes y
estoy muerto :P.

---------- Forwarded message ----------
From: Taft Armandroff
Date: 26 August 2011 14:16
Subject: Type Ia Supernova in M101; Keck Is Participating

** ** ** ** ** ** ** ** ** **

Dear SSC Members and Observers,****

** **

I’d like to share some excitement with you...****

** **

As you likely know, a supernova has exploded in the nearby galaxy M101,
discovered by the Palomar Transient Factory.  This Type Ia supernova is the
nearest ****Type** **Ia**** in a long time.  As you know, observing this
nearby supernova offers great potential benefits.****

** **

A group is using Keck II tonight to observe this supernova, very soon after
its explosion.  They will use our adaptive optics system.  As fate would
have it, the supernova is in a part of the sky that is only observable at
the very start of the night.  Josh Bloom of U.C. Berkeley is leading the
effort, and Alan Stockton is collaborating using UH time.****

** **

Geoff Marcy took a spectrum of the supernova with HIRES and gave it to Peter
Nugent, Josh Bloom, Brad Cenko, and Alex Filippenko for analysis****

** **

I append a couple of accessible published pieces below (Nature News Blog;
Science Daily) on the M101 supernova discovery if you are interested.  Keck
and Lick spectroscopy are mentioned.****

** **

Just wanted to share the excitement of this discovery and that Keck is part
of the worldwide effort to take advantage of this rare opportunity.****

** **

Best,****

Taft****

** **
 *Nearby supernova may illuminate dark energy puzzle - August 25, 2011*

**[image: ptf11kly_arrow-350.jpg]**A Type Ia supernova, the brightest and
most energetic kind of stellar explosion – and the type that astronomers use
to measure the accelerating expansion of the universe – has been spotted in
a nearby galaxy, making it the closest such event in nearly 40 years.****

Astronomers working with the Palomar Transient
Factory<http://www.astro.caltech.edu/ptf/>(PTF), an automated sky
survey based at the Mount Palomar observatory in
****California**** say their robotic telescope detected the new supernova
(arrow) on 23 August in the galaxy M101 located some 21 million light years
away <http://ned.ipac.caltech.edu/cgi-bin/nDistance?name=MESSIER+101>.****

“We are very excited to get one this close,” says ****Oxford** **University*
*** astronomer and PTF collaborator Mark Sullivan. “We essentially
discovered it the day it blew up.”****

The early detection, couple with the supernova’s relative nearness (in
cosmic terms) creates a rare opportunity for researchers trying to refine
their understanding of an important class of stellar explosion. In the
coming hours and days telescopes on the ground and in space, including
the Hubble
Space Telescope <http://hubblesite.org/>, and at the Keck
Observatory<http://www.keckobservatory.org/>on
****Mauna Kea**, **Hawaii****, will be swiveling over to gather data from
the rapidly brightening object.****

"We know it's the youngest **Type** **Ia** ever observed," says Peter Nugent
of Lawrence Berekely National Laboratory in ****Berkeley**, **California****,
who leads the Type Ia search group with PTF. "This thing just shot up out of
nowhere." ****

Now the race is on to accumulate as much data as possible and as quickly as
possible, says Nugent. This will help clarify what goes on in the earliest
stages of a Type 1a supernova, when most of the light is emanating from the
outermost layers of the exploding star. "At this early epoch, the supernova
can change hour to hour," he says.****

A thorough set of observations could catapult this supernova into the ranks
of those few textbook cases that are used by astronomers as callibration
tools for distance measurements. ****

Unlike other kinds of supernovae, triggered when massive stars undergo core
collapse, ****Type** **Ia****’s are produced when white dwarf stars are
pushed over a theoretical mass limit. The result is a thermonuclear
detonation with a well predicted peak brightness, which makes such events
ideal ‘standard candles’ for measuring extragalactic distances. Observations
of ****Type** **Ia**** supernovae in remote galaxies led to the surprising
revelation in 1998 that the expansion of the universe is speeding up over
time due to the presence of dark energy, a poorly understood phenomenon.
Subsequent studies have helped confirm dark energy’s fundamental role in
shaping the cosmos, but the picture depends on astronomers’ understanding of
how ****Type** **Ia**** supernovae shine. Unknown factors in the physics of
****Type** **Ia****’s may have a bearing on the way they are used to
calculate precise distances. ****

“One of the biggest unknowns is the effect of metalicity,” says Sullivan.
Metallicity is a measure of a star’s accumulation of heavier elements
relative to its hydrogen. If the star goes supernova, its metalicity may
influence how bright the explosion ultimately appears. Among the
observations planned for the new supernova are spectroscopic studies across
a broad range of wavelengths, Sullivan says, particularly in the very early
stages of the explosion, “when the effects of metalicity are most profound.”
****

Sullivan predicts that by the time the supernova peaks in early September it
will have a visual magnitude of 9 to 10, placing it within reach of
observers using small telescopes or binoculars under clear, dark skies.****

M101, better known as ‘the Pinwheel Galaxy’ because of its striking spiral
form, is a popular target for astrophotographers. Its
location<http://astronomycentral.co.uk/wp-content/uploads/2010/01/Ursa-major-constellation-map.png>in
the northern constellation of Ursa Major (just above the handle of the
Big Dipper, or the Plough) virtually guarantees that the supernova will be
frequently imaged by amateur astronomers in Europe, the United States and
Japan over the next few weeks and followed closely – potentially for years –
as its luminosity gradually diminishes. ****

Although there has not been a Type Ia supernova as near as this since 1972,
the modern record holder for all supernovae types remains SN1987a, which
exploded in the Large Magellanic Cloud, a satellite system of the Milky Way,
in February 1987 and was visible to the naked eye. A supernova has not been
seen exploding within our own galaxy since 1604. ****

Original at:
http://blogs.nature.com/news/2011/08/bright_supernova_one_of_the_ne.html****

** **

** **

*Scientists Discover an 'Instant Cosmic Classic' Supernova*

* *

*ScienceDaily (Aug. 25, 2011)* — A supernova discovered August 24 is closer
to Earth -- approximately 21 million light-years away -- than any other of
its kind in a generation. Astronomers believe they caught the supernova
within hours of its explosion, a rare feat made possible with a specialized
survey telescope and state-of-the-art computational tools.****

** **

The finding of such a supernova so early and so close has energized the
astronomical community as they are scrambling to observe it with as many
telescopes as possible, including the Hubble Space Telescope.****

Joshua Bloom, assistant professor of astronomy at the **University** of **
California**, ****Berkeley****, called it "the supernova of a generation."
Astronomers at Lawrence Berkeley National Laboratory (Berkeley Lab) and UC
Berkeley, who made the discovery predict that it will be a target for
research for the next decade, making it one of the most-studied supernova in
history.****

** **

The supernova, dubbed PTF 11kly, occurred in the Pinwheel Galaxy, located in
the "Big Dipper," otherwise known as the Ursa Major constellation. It was
discovered by the Palomar Transient Factory (PTF) survey, which is designed
to observe and uncover astronomical events as they happen.****

** **

"We caught this supernova very soon after explosion. PTF 11kly is getting
brighter by the minute. It's already 20 times brighter than it was
yesterday," said Peter Nugent, the senior scientist at Berkeley Lab who
first spotted the supernova. Nugent is also an adjunct professor of
astronomy at UC Berkeley. "Observing PTF 11kly unfold should be a wild ride.
It is an instant cosmic classic."****

** **

He credits supercomputers at the National Energy Research Scientific
Computing Center (NERSC), a Department of Energy supercomputing center at
Berkeley Lab, as well as high-speed networks with uncovering this rare event
in the nick of time.****

** **

The PTF survey uses a robotic telescope mounted on the 48-inch Samuel Oschin
Telescope at Palomar Observatory in **Southern California** to scan the sky
nightly. As soon as the observations are taken, the data travels more than
400 miles to NERSC via the National Science Foundation's High Performance
Wireless Research and Education Network and DOE's Energy Sciences Network
(ESnet). At NERSC, computers running machine learning algorithms in the
Real-time Transient Detection Pipeline scan through the data and identify
events to follow up on. Within hours of identifying PTF 11kly, this
automated system sent the coordinates to telescopes around the world for
follow-up observations.****

** **

Three hours after the automated PTF pipeline identified this supernova
candidate, telescopes in the Canary Islands (****Spain****) had captured
unique "light signatures," or spectra, of the event. Twelve hours later, his
team had observed the event with a suite of telescopes including the Lick
Observatory (California), and Keck Observatory (Hawaii) and determined the
supernova belongs to a special category, called Type Ia. Nugent notes that
this is the earliest spectrum ever taken of a Type Ia supernova.****

** **

"****Type** **Ia**** supernova are the kind we use to measure the expansion
of the Universe. Seeing one explode so close by allows us to study these
events in unprecedented detail," said Mark Sullivan, the ****Oxford** **
University**** team leader who was among the first to follow up on this
detection.****

** **

"We still do not know for sure what causes such explosions," said Weidong
Li, senior scientist at UC Berkeley and collaborator of Nugent. "We are
using images from the Hubble Space Telescope, taken fortuitously years
before an explosion to search for clues to the event's origin."****

** **

The team will be watching carefully over the next few weeks, and an urgent
request to NASA yesterday means the Hubble Space Telescope will begin
studying the supernova's chemistry and physics this weekend.****

Catching supernovae so early allows a rare glimpse at the outer layers of
the supernova, which contain hints about what kind of star exploded. "When
you catch them this early, mixed in with the explosion you can actually see
unburned bits from star that exploded! It is remarkable," said Andrew Howell
of UC Santa Barbara/Las Cumbres Global Telescope Network. "We are finding
new clues to solving the mystery of the origin of these supernovae that has
perplexed us for 70 years. Despite looking at thousands of supernovae, I've
never seen anything like this before."****

** **

"The ability to process all of this data in near real-time and share our
results with collaborators around the globe through the Science Gateway at
NERSC is an invaluable tool for following up on supernova events," says
Nugent. "We wouldn't have been able to detect and observe this candidate as
soon as we did without the resources at NERSC."****

** **

At a mere 21 million light-years from Earth, a relatively small distance by
astronomical standards, the supernova is still getting brighter, and might
even be visible with good binoculars in ten days' time, appearing brighter
than any other supernova of its type in the last 30 years.****

** **

"The best time to see this exploding star will be just after evening
twilight in the Northern hemisphere in a week or so," said Oxford's
Sullivan. "You'll need dark skies and a good pair of binoculars, although a
small telescope would be even better."****

** **

The scientists in the PTF have discovered more than 1,000 supernovae since
it started operating in 2008, but they believe this could be their most
significant discovery yet. The last time a supernova of this sort occurred
so close was in 1986, but Nugent notes that this one was peculiar and
heavily obscured by dust.****

'"Before that, you'd have to go back to 1972, 1937 and 1572 to find more
nearby ****Type** **Ia**** supernovae," says Nugent.****

** **

The Palomar Transient Factory is a survey operated a Palomar Observatory by
the California Institute of Technology on behalf of a worldwide consortium
of partner institutions. Collaborators on PTF 11kly with Nugent, Bloom and
Li are Brad Cenko, Alex V. Filippenko, Geoffrey Marcy, Adam Miller (UC
Berkeley), Rollin C. Thomas (**Lawrence** **Berkeley** National Laboratory),
Sullivan (****Oxford** **University****), and Andrew Howell (UC Santa
Barbara/Las Cumbres Global Telescope Network).****

** **

Original at: http://www.sciencedaily.com/releases/2011/08/110825164936.htm**
**

** **

** **

 _____________________________________________________________****

***Taft Armandroff***
Director

****

****W.M. Keck Observatory
65-1120 Mamalahoa Hwy**
**Kamuela**, **HI** **96743********

tarmandroff en keck.hawaii.edu
phone: 808.885.7887
fax: 808.885.4464****

** **

** **

-- 
Guido Moyano Loyola, PhD Student
Centre for Astrophysics and Supercomputing
Swinburne University of Technology
Hawthorn, Melbourne, VIC 3122, Australia
Phone: +61392148707
Office AR 310
http://astronomy.swin.edu.au/staff/gmoyano.html
------------ próxima parte ------------
Se ha borrado un adjunto en formato HTML...
URL: <https://www.fcaglp.unlp.edu.ar/mailman/private/alumnos/attachments/20110826/d3d9bda0/attachment-0001.html>
------------ próxima parte ------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 14711 bytes
Desc: no disponible
URL: <https://www.fcaglp.unlp.edu.ar/mailman/private/alumnos/attachments/20110826/d3d9bda0/attachment-0001.jpg>