Found images: 2017 January

[bystander]

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Have you seen a great image or video somewhere that you think would make a great APOD? Nominate it for APOD! Please post as much information here as you have about the image/video with a link to any source(s) for it you know of here, and the editors will take a look.

When posting the image itself, please do not post anything larger than a thumbnail here; please honor the copyright holder's copyright.

Please keep hotlinked images under 400K.

Thank you!

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[bystander]

When Galaxies Collide (IRAS 14348-1447)
ESA Hubble Picture of the Week | 2017 Jan 02

[img3="Credit: ESA/Hubble & NASA"]https://cdn.spacetelescope.org/archives ... w1701a.jpg[/img3][hr][/hr]

This delicate smudge in deep space is far more turbulent than it first appears. Known as IRAS 14348-1447 — a name derived in part from that of its discoverer, the Infrared Astronomical Satellite (IRAS for short) — this celestial object is actually a combination of two gas-rich spiral galaxies. This doomed duo approached one another too closely in the past, gravity causing them to affect and tug at each other and slowly, destructively, merge into one. The image was taken by Hubble’s Advanced Camera for Surveys (ACS).

IRAS 14348-1447 is located over a billion light-years away from us. It is one of the most gas-rich examples known of an ultraluminous infrared galaxy, a class of cosmic objects that shine characteristically — and incredibly — brightly in the infrared part of the spectrum. Almost 95% of the energy emitted by IRAS 14348-1447 is in the far-infrared!

The huge amount of molecular gas within IRAS 14348-1447 fuels its emission, and undergoes a number of dynamical processes as it interacts and moves around; these very same mechanisms are responsible for IRAS 14348-1447’s own whirling and ethereal appearance, creating prominent tails and wisps extending away from the main body of the galaxy.

[starsurfer]

Keenan's System (NGC 5216-8)
http://www.caelumobservatory.com/gallery/n5216.shtml
Copyright: Adam Block/Mount Lemmon SkyCenter/University of Arizona

Click to view full size image

[starsurfer]

NGC 90
http://bf-astro.com/ngc90/ngc90.htm
Copyright: Bob Franke

[starsurfer]

M24
http://www.astrosurf.com/ilizaso/orriak ... Q_U16m.htm
Copyright: Iñaki Lizaso

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Taurus Molecular Cloud
http://www.astrobin.com/274368/C/
Copyright: Tero Turunen

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LDN 673
http://astrophotography.aa6g.org/Astrop ... f8300.html
Copyright: Chuck Vaughn

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LDN 988
http://www.starpointing.com/ccd/ldn988.html
Copyright: Fabian Neyer

[starsurfer]

LDN 1622
http://www.atacama-photographic-observa ... .php?id=59
Copyright: Thierry Demange, Richard Galli and Thomas Petit

[Ann]

NGC 1313
http://www.billionsandbillions.com/topsy-turvy.html

Click to view full size image

NGC 1313.
Photo: Warren Keller.

I just saw that Sandgirl, our eminent poster of astroimages here at Starship Asterisk*, had made her 1313th post, and then I couldn't resist. NGC 1313 is one of my favorite galaxies, with an NGC number that is easy to remember to boot, and when I found this great picture of NGC 1313 by Warren Keller, I just had to post it!

And it is for Sandgirl!

Ann

[Ann]

The Earth and Moon as seen from Mars
http://astronomynow.com/2017/01/06/your ... from-mars/

Click to view full size image

The Earth and Moon as seen from Mars.
Image: NASA/JPL-Caltech/University of Arizona.

Astronomy Now wrote:
From the most powerful telescope orbiting Mars comes a new view of Earth and its moon, showing continent-size detail on the planet and the relative size of the Moon.

The image combines two separate exposures taken on 20 November 2016, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. The images were taken to calibrate HiRISE data, since the reflectance of the Moon’s Earth-facing side is well known. For presentation, the exposures were processed separately to optimise detail visible on both Earth and the Moon. The Moon is much darker than Earth and would barely be visible if shown at the same brightness scale as Earth.

The combined view retains the correct positions and sizes of the two bodies relative to each other. The distance between Earth and the moon is about 30 times the diameter of Earth. Earth and the moon appear closer than they actually are in this image because the observation was planned for a time at which the moon was almost directly behind Earth, from Mars’ point of view, to see the Earth-facing side of the moon.

In the image, the reddish feature near the middle of the face of Earth is Australia. When the component images were taken, Mars was about 205 million kilometres (127 million miles) from Earth.

With HiRISE and five other instruments, the Mars Reconnaissance Orbiter has been investigating Mars since 2006.

[bystander]

The Earth and Moon as seen from Mars

Your Home Planet, as Seen From Mars
NASA | JPL-Caltech | HiRISE | 2017 Jan 07

Earth and Its Moon, as Seen From Mars
NASA | JPL-Caltech | Space Images | Photo Journal | HiRISE | 2017 Jan 06

[starsurfer]

Gem Cluster (NGC 3293)
http://www.astropilar.com.ar/cumulos/NGC3293_1.html
Copyright: Ezequiel Bellocchio

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NGC 602
http://www.pbase.com/tango33/image/163062619
Copyright: Kfir Simon

[bystander]

A Black Hole of Puzzling Lightness
ESA Hubble Picture of the Week | 2017 Jan 09

[img3="Credit: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt (geckzilla)"]https://cdn.spacetelescope.org/archives ... w1702a.jpg[/img3][hr][/hr]

This image taken with the Advanced Camera for Surveys (ACS) onboard the NASA/ESA Hubble Space Telescope captures a galaxy in the Virgo constellation. This camera was installed in 2002, and its wide field of view is double that of its predecessor, capturing superb images with sharp image quality and enhanced sensitivity that can be seen here.

The beautiful spiral galaxy visible in the centre of the image is catchily known as RX J1140.1+0307, and it presents an interesting puzzle. At first glance, this galaxy appears to be a normal spiral galaxy, much like the Milky Way, but first appearances can be deceptive!

The Milky Way galaxy, like most large galaxies, has a supermassive black hole at its centre, but some galaxies are centred on lighter, intermediate-mass black holes. RX J1140.1+0307 is such a galaxy — in fact, it is centred on one of the lowest black hole masses known in any luminous galactic core. What puzzles scientists about this particular galaxy is that the calculations don’t add up. With such a relatively low mass for the central black hole, models for the emission from the object cannot explain the observed spectrum; unless there are other mechanisms at play in the interactions between the inner and outer parts of the accretion disc surrounding the black hole.

[Ann]

Fascinating!

Looking at RX J1140.1+0307, however, I'm not entirely surprised at its lightweight central black hole. It is clear enough from the picture that the galaxy is dominated by young blue stars, and such galaxies produce a lot of bang for their buck - in other words, they are quite luminous for their mass. Even though the picture clearly shows us the underlying old yellow population of RX J1140.1+0307, I still think that the galaxy itself holds relatively little mass. It also seems probable that the bright blue population is the product of a relatively recent starburst. If that is the case, the black hole of RX J1140.1+0307 may have been sitting quietly for billions of years, surrounded by a tired old yellow population that didn't do a good job of feeding the black hole a lot of new mass at all. Is the galaxy moderately isolated? Well, I can see a bright yellow lenticular galaxy quite close to it. May the galaxies have relatively recently met? Maybe that triggered a recent starburst in RX J1140.1+0307?

I decided to compare RX J1140.1+0307 with M101, the bluest of the Messier galaxies. To my frustration, I could find no information about the central black hole of M101 at all - I could only find information about a stellar-mass black hole there!

My point is that I believe that M101, which is completely dominated by young blue stars, in all probability has a lightweight central black hole. If its central black hole was massive, I think we would know more about it. I think RX J1140.1+0307 may be somewhat similar.

But I agree that the core of RX J1140.1+0307 seems surprisingly bright for a very lightweight central black hole.

Ann

[starsurfer]

IC 447
http://cosmicphotos.com/gallery/image.p ... lbum_id=11
Copyright: Jason Jennings

Click to view full size image

[starsurfer]

NGC 1512
http://www.billionsandbillions.com/ngc_1512.html
Copyright: Warren Keller/SSRO

Click to view full size image

[stavroshios]

ORION ABOVE PLASTIRAS LAKE by Stavros Hios, on Flickr

[starsurfer]

Pencil Nebula (NGC 2736) and RCW 38
http://www.tvdavisastropics.com/astroim ... 0000b5.htm
Copyright: Thomas Davis

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Tycho's Supernova Remnant
http://outters.fr/wp/sn1572-ha-rvb/
Copyright: Nicolas Outters

This is the remnant of a supernova that exploded in 1572 and is named after Tycho Brahe.

[Fakeastropix]

John Napper's image of a gravitationally lensed Quasar 7.8 billion light years away I find absolutely astonishing. Captured under England's light polluted skies with a C11. Copyright: John Napper. https://www.flickr.com/photos/67647466@ ... ateposted/

[starsurfer]

M101
https://www.noao.edu/image_gallery/html/im1281.html
Copyright: T.A. Rector (University of Alaska Anchorage) and H. Schweiker (WIYN and NOAO/AURA/NSF)

[starsurfer]

NGC 7098
http://www.pbase.com/strongmanmike2002/ ... _in_octans
Copyright: Michael Sidonio

[bystander]

A Slice of Sagittarius
ESA Hubble Picture of the Week | 2017 Jan 16

[img3="Credit: ESA/Hubble & NASA"]https://cdn.spacetelescope.org/archives ... w1703a.jpg[/img3][hr][/hr]

This stunning image, captured by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS), shows part of the sky in the constellation of Sagittarius (The Archer). The region is rendered in exquisite detail — deep red and bright blue stars are scattered across the frame, set against a background of thousands of more distant stars and galaxies. Two features are particularly striking: the colours of the stars, and the dramatic crosses that burst from the centres of the brightest bodies.

While some of the colours in this frame have been enhanced and tweaked during the process of creating the image from the observational data, different stars do indeed glow in different colours. Stars differ in colour according to their surface temperature: very hot stars are blue or white, while cooler stars are redder. They may be cooler because they are smaller, or because they are very old and have entered the red giant phase, when an old star expands and cools dramatically as its core collapses.

The crosses are nothing to do with the stars themselves, and, because Hubble orbits above Earth’s atmosphere, nor are they due to any kind of atmospheric disturbance. They are actually known as diffraction spikes, and are caused by the structure of the telescope itself. Like all big modern telescopes, Hubble uses mirrors to capture light and form images. Its secondary mirror is supported by struts, called telescope spiders, arranged in a cross formation, and they diffract the incoming light. Diffraction is the slight bending of light as it passes near the edge of an object. Every cross in this image is due to a single set of struts within Hubble itself! Whilst the spikes are technically an inaccuracy, many astrophotographers choose to emphasise and celebrate them as a beautiful feature of their images.