Postcard from the Summit – First Target of the Night
Tag: Keck
Discovery of the Most Distant Galaxy in the Cosmic Dawn
W. M. Keck Observatory press release…
A team of astronomers has used the Subaru Telescope and the W. M. Keck Observatory to discover the most distant galaxy yet, at 12.91 billion light-years from the Earth. This new galaxy, dubbed SXDF-NB1006-2, is slightly farther away than the previous record holder, galaxy GN-108036, which was found last year.
To identify SXDF-NB1006-2, the team used the Subaru Telescope to observe a total of 37 hours in seven nights in two wide fields of the sky. The team, led by Takatoshi Shibuya (The Graduate University for Advanced Studies, Japan), Dr. Nobunari Kashikawa (National Astronomical Observatory of Japan), Dr. Kazuaki Ota (Kyoto University), and Dr. Masanori Iye (National Astronomical Observatory of Japan), carefully processed the images they had obtained. Shibuya measured the color of 58,733 objects in the images and identified four galaxy candidates at a redshift of 7.3, which translates into about 12.9 billion light-years. A careful investigation of the brightness variation of the objects allowed the team to narrow down the number of candidates to two.
Color composite image of the Subaru XMM-Newton Deep Survey Field of galaxy SXDF-NB1006-2, credit NAOJ
Finally, the team needed to make spectroscopic observations to confirm the nature of these candidates. They observed the two galaxy candidates with two spectrographs, the Faint Object Camera and Spectrograph (FOCAS) on the Subaru Telescope and the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II Telescope, and identified one candidate for which a characteristic emission line of distant galaxies could be detected. The results are slated to be published in the June 20, 2012, edition of Astrophysical Journal.
In addition to locating the galaxy, the team’s research verified that the proportion of neutral hydrogen gas in the 750-million-year-old early Universe was higher than it is today. These findings help to decipher the early Universe during the “cosmic dawn,” when the light of ancient celestial objects and structures first appeared. They concluded that about 80 percent of the hydrogen gas in the ancient Universe, 12.91 billion years ago at a redshift of 7.2, was neutral.
Continue reading “Discovery of the Most Distant Galaxy in the Cosmic Dawn”
The Transit of Venus
We did the Transit of Venus right.
The plan was to stream the transit live from the summit. With access to the Keck facilities we had internet, a comfortable break room, and an excellent vantage point from which to view the entire transit. It sounded so easy at first, just put a camera on a telescope and connect it to the computer for the duration. Easy, in concept. The reality? Not so much.
It was an incredible amount of work. I had spent several days during the preceding weeks preparing the gear for transit. I admit some of that was fun, an excuse to get the gear out in the day and look at the Sun, even photograph Venus quite near the Sun.
The webcast team consisted of three people, Larry O’Hanlon, the Keck PIO, Mark Senft, a volunteer from our astronomy club, and myself. Larry and I met a HQ to begin our drive up the mountain at 8am.
At Hale Pohaku we picked up Mark and enjoyed breakfast. Here we found a massive buildup in progress, a gathering of troops… Visitor center staff, Hawai’i County police and fire, and the Mauna Kea Rangers, all present in force. Stephanie Nagata, the director of the Office of Mauna Kea Management helped man the roadblock. Stewart Hunter, the head of Mauna Kea Support Services with her in an orange vest. Their preparations looked to be necessary, three hours prior to first contact the crowds of transit tourists were already growing.
Continue reading “The Transit of Venus”Keck Lecture – Dr. Brian Siana
On Thursday, May 10, 2012, Keck Observatory hosted a live webcast of an astronomy talk by Dr. Brian Siana of the University of California at Riverside. Below is the recording of that talk, which was delivered to a live audience at the Kahilu Theatre in Kamuela-Waimea, Hawaii.
The first galaxies had an extraordinary impact on the young universe. Their ultraviolet light destroyed nearly all of the atoms in the cosmos. This process, called reionization, had severe consequences for galaxies trying to form thereafter. Unfortunately, we have no idea how it happened. In galaxies today ultraviolet light cannot escape, so the first galaxies must have been very different from those we see today. Dr. Siana will describe the quest to detect these first galaxies and their impact on the early universe.
Astronomy Haiku
You remember haiku? Three lines, the first line with five syllables, a second line with seven syllables, and a last line with five syllables. It may be poetry, but this is easy poetry to write, a short verse with an elegant cadence.
For an AstroDay activity, Keck held an astronomy haiku project. We have a stack of entries we are just now getting a chance to read. Winners are not yet decided, but I have found a few that are wonderful, and worth giving some recognition to.
I should be clear, these are my favorites! Not necessarily the contest winners.
Telescopes are great
They make you see very far
I love telescopes
-Madison Kobayashi (age 9)
Stars shining brightly
I look to them for comfort
In them I find you
-Lacey Siweila
Lacey is over 18 and not eligible for a prize in the contest. She knew this and enters a poem anyway. You have to love that!
The Moon is so bright
The stars help light up the night
Let’s lay out tonight
– Micah Timbresa (age 7)
All poems reproduced with permission.
Keck Lecture Webcast
Tonight’s Keck lecture looks to be an interesting one, discussing the very early ages of the universe in the few million years immediately after the Big Bang. I will be there, I hope you can be there as well.
Dr. Brian Siana
How Stars Destroyed Most of the Atoms in the Universe
Kahilu Theater
Thursday, May 10th
7:00pm
Of course we will be web-casting the lecture live for those unable to attend…
Keck Lecture at Kahilu May 10
Dr. Brian Siana
How Stars Destroyed Most of the Atoms in the Universe
Kahilu Theater
Thursday, May 10th
7:00pm
The first galaxies had an extraordinary impact on the young universe. Their ultraviolet light destroyed nearly all of the atoms in the cosmos. This process, called reionization, had severe consequences for galaxies trying to form thereafter. Unfortunately, we have no idea how it happened. In galaxies today ultraviolet light cannot escape, so the first galaxies must have been very different from those we see today. Dr. Siana will describe the quest to detect these first galaxies and their impact on the early universe.
There is no charge for admission to any events in the Makana series.
Presented by W.M. Keck Observatory. This event will also be streamed live on the Keck Observatory website.
Employment Opportunity at Keck – Software Engineer
W. M. Keck Observatory position announcement…
The Observatory seeks a Software Engineer responsible for a variety of duties related to developing, deploying and optimizing software for control solutions used at the observatory and integration of partner developed science instruments. The successful candidate will enjoy a comprehensive benefits package while residing in one of the world’s most uniquely beautiful and diverse locations.
The candidate is expected to have a minimum of 5 years’ proven experience developing and integrating distributed control software solutions for engineering or scientific applications with involvement in all aspects of the software life cycle from specification through deployment.
The candidate is expected to have sound knowledge of modern software engineering practices. Practical experience in the following is required: strong C/C++ with significant O-O design and development; UNIX platform development environment using the gnu tool chain under Linux or Solaris; working with communication middleware such as RPC, RMI, ICE or messaging systems; working with real-time OS like VxWorks or RT Linux; User Interface development with Tcl/Tk, Java, Qt, Python or other toolkits.
The ideal candidate should be a motivated, self-starter who can collaborate effectively across disciplines in a fast paced environment. Experience working with EPICS at an astronomical observatory or high energy physics experiment facility and experience with driver development and motion control are highly desirable.
This position requires you to submit your resume on-line at: http://keckobservatory.iapplicants.com/ViewJob-304399.html with your cover letter that states why you are uniquely qualified for the position.
Additional information about WMKO and this position may be found on our web site at www.keckobservatory.org. EEO Employer
‘Ridiculously’ Dim Bevy of Stars Found Beyond Milky Way
W. M. Keck Observatory press release…
A team of American, Canadian and Chilean astronomers have stumbled onto a remarkably faint cluster of stars orbiting the Milky Way that puts out as much light as only 120 modest Sun-like stars. The tiny cluster, called Muñoz 1, was discovered near a dwarf galaxy in a survey of satellites around the Milky Way using the Canada-France-Hawaii Telescope (CFHT) and confirmed using the Keck II telescope, both of which are on Mauna Kea, Hawaii.
“What’s neat about this is it’s the dimmest globular cluster ever found,” said Ricardo Muñoz, an astronomer at the University of Chile and the discoverer of the cluster. A globular cluster is a spherical group of stars bound to each other by gravity so that they orbit around a galaxy as a unit.
“While I was working on the Ursa Minor dwarf galaxy I noticed there was this tiny little object close by,” Muñoz recalled. He made the discovery while he was a postdoctoral associate at Yale University. Most globular clusters have in the range of 100,000 stars. Muñoz 1 has something like 500 stars. “This is very surprising,” he said.
The Muñoz 1 globular cluster is seen to the right of the Ursa Minor dwarf galaxy in this image from the Canada-France-Hawaii Telescope MegaCam imager.
“It’s ridiculously dim,” agreed Yale astronomer Marla Geha. “There are individual stars that would far outshine this entire globular cluster.” That puts Muñoz 1 head-to-head with the Segue 3 globular cluster (also orbiting the Milky Way) as the dimmest troupe of old stars ever found.
Muñoz 1’s discovery was the result of a survey done with the CFHT MegaCam imager in 2009 and 2010. It was then confirmed by spectroscopic study using the Deep Extragalactic Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II telescope. The researchers will be publishing their results soon in The Astrophysical Journal Letters.
The Keck data was critical for the study, said Geha, because it sorted out whether or not Muñoz 1 and the Ursa Minor dwarf galaxy were moving together.
“Nearly every galaxy has an entourage of globular clusters,” said Geha, “so we first thought that Muñoz 1 might be associated with the nearby Ursa Minor dwarf galaxy.” By using spectroscopic data to measure the relative velocities of the cluster and the dwarf galaxy, they discovered quite the opposite was the case.
“The velocities turned out to be wildly different,” said Geha. So the fact that they are near each other is just a coincidence, she said. What has been seen is more like a single snapshot of two cars traveling near each other and apparently together, but they really have different destinations and are traveling at very different speeds. Analysis of the brightness and colors of the stars belonging to Muñoz 1 and Ursa Minor also suggests that the tiny cluster is actually located about 100,000 light years in front of the dwarf galaxy.
As for how Muñoz 1 came to be so dim, a likely scenario is that it has gradually lost stars over the eons, said Geha. It’s also possible it was stripped of stars by passing through the Milky Way. But the direction of the cluster’s movement is not yet known, so it’s not known whether it has passed through the Milky Way.
Perhaps the most intriguing aspect of the discovery is the possibility that Muñoz 1 may be hinting that there are many more such globular clusters in the Galactic halo. After all, the CFHT survey covered only 40 square degrees of sky out of 40,000 square degrees in the entire sky.
“Assuming that we’re not just lucky to have found something very rare, there could be many others out there,” said Geha.
“To truly understand its nature, we will need to measure its mass,” added Munoz. To do that, astronomers would need to measure the velocities of individual stars in the cluster and see how they move with relation to each other. That, in turn, reveals the overall mass of the cluster. A lot of mass would suggest there is a lot of dark matter holding the cluster together, and maybe even qualify the cluster as the smallest, darkest galaxy ever discovered. Right now the Segue 1 dwarf galaxy holds that record. Geha was also involved in measurements with the Keck DEIMOS instrument that confirmed the nature of Segue 1.
“The goal of this survey was to understand the difference between dwarf galaxies and globular clusters,” said Geha. Muñoz 1 suggests there may be plenty of borderline objects out there waiting to be found, which could help sort that matter out.
A pdf of the paper is available at http://www.cfht.hawaii.edu/en/news/Munoz1/munoz12.pdf.
An Offering
Early this week we were surprised to find a set of plumeria lei on one of the pillars in front of our building. Bright white and yellow, the scent of the flowers hanging heavy around the loading dock door. Quite a contrast in a world of dark red cinder and cold, a bit of the tropics that lie far below the summit.
Why would someone leave the lei at our door? A thank-you for what we do? A gentle protest at our presence on the mountain? I wonder as we drive down, lost in thought.