distant-traveller
distant-traveller:

New mass map of a distant galaxy cluster is the most precise yet



Astronomers using the NASA/ESA Hubble Space Telescope have mapped the mass within a galaxy cluster more precisely than ever before. Created using observations from Hubble’s Frontier Fields observing programme, the map shows the amount and distribution of mass within MCS J0416.1–2403, a massive galaxy cluster found to be 160 trillion times the mass of the Sun. The detail in this mass map was made possible thanks to the unprecedented depth of data provided by new Hubble observations, and the cosmic phenomenon known as strong gravitational lensing.
Measuring the amount and distribution of mass within distant objects in the Universe can be very difficult. A trick often used by astronomers is to explore the contents of large clusters of galaxies by studying the gravitational effects they have on the light from very distant objects beyond them. This is one of the main goals of Hubble’s Frontier Fields, an ambitious observing programme scanning six different galaxy clusters — including MCS J0416.1–2403, the cluster shown in this stunning new image.
Large clumps of mass in the Universe warp and distort the space-time around them. Acting like lenses, they appear to magnify and bend light that travels through them from more distant objects.
Despite their large masses, the effect of galaxy clusters on their surroundings is usually quite minimal. For the most part they cause what is known as weak lensing, making even more distant sources appear as only slightly more elliptical or smeared across the sky. However, when the cluster is large and dense enough and the alignment of cluster and distant object is just right, the effects can be more dramatic. The images of normal galaxies can be transformed into rings and sweeping arcs of light, even appearing several times within the same image. This effect is known as strong lensing, and it is this phenomenon, seen around the six galaxy clusters targeted by the Frontier Fields programme, that has been used to map the mass distribution of MCS J0416.1–2403, using the new Hubble data.
Using Hubble’s Advanced Camera for Surveys, the astronomers identified 51 new multiply imaged galaxies around the cluster, quadrupling the number found in previous surveys and bringing the grand total of lensed galaxies to 68. Because these galaxies are seen several times this equates to almost 200 individual strongly lensed images which can be seen across the frame. This effect has allowed Jauzac and her colleagues to calculate the distribution of visible and dark matter in the cluster and produce a highly constrained map of its mass..
The total mass within MCS J0416.1-2403 — modelled to be over 650 000 light-years across — was found to be 160 trillion times the mass of the Sun. This measurement is several times more precise than any other cluster map, and is the most precise ever produced. By precisely pinpointing where the mass resides within clusters like this one, the astronomers are also measuring the warping of space-time with high precision.

Image credit: ESA/Hubble, NASA, HST Frontier Fields

distant-traveller:

New mass map of a distant galaxy cluster is the most precise yet

Astronomers using the NASA/ESA Hubble Space Telescope have mapped the mass within a galaxy cluster more precisely than ever before. Created using observations from Hubble’s Frontier Fields observing programme, the map shows the amount and distribution of mass within MCS J0416.1–2403, a massive galaxy cluster found to be 160 trillion times the mass of the Sun. The detail in this mass map was made possible thanks to the unprecedented depth of data provided by new Hubble observations, and the cosmic phenomenon known as strong gravitational lensing.

Measuring the amount and distribution of mass within distant objects in the Universe can be very difficult. A trick often used by astronomers is to explore the contents of large clusters of galaxies by studying the gravitational effects they have on the light from very distant objects beyond them. This is one of the main goals of Hubble’s Frontier Fields, an ambitious observing programme scanning six different galaxy clusters — including MCS J0416.1–2403, the cluster shown in this stunning new image.

Large clumps of mass in the Universe warp and distort the space-time around them. Acting like lenses, they appear to magnify and bend light that travels through them from more distant objects.

Despite their large masses, the effect of galaxy clusters on their surroundings is usually quite minimal. For the most part they cause what is known as weak lensing, making even more distant sources appear as only slightly more elliptical or smeared across the sky. However, when the cluster is large and dense enough and the alignment of cluster and distant object is just right, the effects can be more dramatic. The images of normal galaxies can be transformed into rings and sweeping arcs of light, even appearing several times within the same image. This effect is known as strong lensing, and it is this phenomenon, seen around the six galaxy clusters targeted by the Frontier Fields programme, that has been used to map the mass distribution of MCS J0416.1–2403, using the new Hubble data.

Using Hubble’s Advanced Camera for Surveys, the astronomers identified 51 new multiply imaged galaxies around the cluster, quadrupling the number found in previous surveys and bringing the grand total of lensed galaxies to 68. Because these galaxies are seen several times this equates to almost 200 individual strongly lensed images which can be seen across the frame. This effect has allowed Jauzac and her colleagues to calculate the distribution of visible and dark matter in the cluster and produce a highly constrained map of its mass..

The total mass within MCS J0416.1-2403 — modelled to be over 650 000 light-years across — was found to be 160 trillion times the mass of the Sun. This measurement is several times more precise than any other cluster map, and is the most precise ever produced. By precisely pinpointing where the mass resides within clusters like this one, the astronomers are also measuring the warping of space-time with high precision.

Image credit: ESA/HubbleNASAHST Frontier Fields

lamus-dworski

COSTUMES: early medieval Poland

lamus-dworski:

Various Slavic costumes (with the focus on dresses, jewellery and accessories) and a few ones of noticeable Viking influences. All pictures are from Rękawka 2014 - the annual Slavic festival at the Krakus Mound (Kopiec Krakusa) in Kraków, Poland. 

Photographs © Ilja Van de Pavert (ilvic), who catched a lot of temple rings (in Polish: kabłączki skroniowe and larger zausznice), very characteristic for the Slavs:

Here’s a nicely detailed Viking outfit:

More shots after the cut.

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todaysdocument
todaysdocument:

Forrest Gump at the Archives
Twenty years ago the film Forrest Gump was released in theaters on July 6, 1994.  In commemoration of the 20th anniversary, colleagues in the National Archives Media Preservation Lab have scoured NARA’s holdings to find a few examples of archival footage that made its way into the movie.
The original archival footage features a young man named Pelton Stewart. Stewart met Nixon in 1971 to be recognized as the Boys Club of America, “Boy of the Year.” The archival footage seen here comes from the Richard Nixon Presidential Library and Museum in Yorba Linda, California. It is part of the Naval Photographic Center Film collection.
In the movie, Forrest is recognized as the U.S. Ping Pong team’s “Player of the Year”. After receiving the award, the president recommends that Forrest stay at the Watergate hotel. Unfortunately for Forrest, people in the office building across the street are looking for “a fuse box or somethin’” and their flashlights keep him awake. He suggests that maintenance man check it out.
See Media Matters » Forrest Gump at the Archives for more historical clips paired with their “Gumpized” versions.



Still images were taken from:  
Nixon Naval Photographic Center Film Collection. ID: 1211-050-71, Date: April 9, 1971
Forrest Gump (1994), Paramount Pictures.

todaysdocument:

Forrest Gump at the Archives

Twenty years ago the film Forrest Gump was released in theaters on July 6, 1994.  In commemoration of the 20th anniversary, colleagues in the National Archives Media Preservation Lab have scoured NARA’s holdings to find a few examples of archival footage that made its way into the movie.

The original archival footage features a young man named Pelton Stewart. Stewart met Nixon in 1971 to be recognized as the Boys Club of America, “Boy of the Year.” The archival footage seen here comes from the Richard Nixon Presidential Library and Museum in Yorba Linda, California. It is part of the Naval Photographic Center Film collection.

In the movie, Forrest is recognized as the U.S. Ping Pong team’s “Player of the Year”. After receiving the award, the president recommends that Forrest stay at the Watergate hotel. Unfortunately for Forrest, people in the office building across the street are looking for “a fuse box or somethin’” and their flashlights keep him awake. He suggests that maintenance man check it out.

See Media Matters » Forrest Gump at the Archives for more historical clips paired with their “Gumpized” versions.

Still images were taken from:  

Nixon Naval Photographic Center Film Collection. ID: 1211-050-71, Date: April 9, 1971

Forrest Gump (1994), Paramount Pictures.