Unexpected Early Spiral Galaxy

Spiral
Composite of BX442 from Hubble Space Telescope and Keck Telescope in Hawaii
Image Credit: David Law; Dunlap Institute for Astronomy and Astrophysics

Only one galaxy with a redshift (z) greater than 2 (about 10 billion years ago) has been observed, but may be a merger viewed at an odd angle.

Now, astronomers report in the 19 July issue of Nature the discovery of a primordial galaxy (Q2343-BX442) at z = 2.18 with three distinct spiral arms.

The images were from the Hubble Space Telescope Wide-Field Camera 3 (HST/WFC3), and BX442 was the only galaxy with a spiral shape among the 306 galaxies surveyed at this depth (z between 1.5 and 3.6). A small companion was observed, and the astronomers note that the collision of such a companion with BX442 can produce the spiral arms that are observed. If this is the case, they expect the galaxy to relax into a more primitive shape within the next 100 million years.

Is Pluto A Binary Dwarf Planet?

Pluto Binary
Four Tiny Satellites Orbit the Pluto-Charon Binary
Image Credit: NASA / ESA / and M. Showalter (SETI Institute)

With the discovery by the Hubble Space Telescope of a fifth tiny moon orbiting Pluto, interest continues to mount about this peculiar system.

Now, there is a suggestion on Discovery.com that the system is actually a Double Planet with four moons (see the image).

The four tiny moons, all discovered by Hubble in the past seven years, do not orbit Pluto itself. Instead, they orbit the center of mass of the Pluto-Charon system.

Charon is 12% the mass of Pluto, and could well qualify as a Kuiper Belt Object (KBO) and is perhaps a dwarf planet itself.

Ceres is a dwarf planet in the Asteroid belt, with a mass of 0.000 15 that of Earth. Pluto’s mass is 0.002 2 of Earth, which would make Charon’s mass 0.000 27 that of Earth (more than Ceres).

Andromeda and The Milky Way – Collision in 3, 2, 1…

…billion years.

Today
Looking From Our Milky Way toward the Andromeda Galaxy
Image Credit: NASA; ESA; Z. Levay and R. van der Marel, STScI; T. Hallas, and A. Mellinger

With a small telescope, you can see the Andromeda Galaxy as a thin disk near the top of the image, and just off to the left side of the Milky Way, which stretches from top to bottom.

Thanks to the four refurbishing missions by the Space Shuttle, NASA has been able to gather extended data on the motion of the Andromeda Galaxy and the Milky Way. Based in this data, we now know how and when the two galaxies will collide.

Below, Andromeda and the Milky Way move closer, pass each other in a burst of star formation due to the tidal disruption, and eventually coalesce into an Elliptical Galaxy.

1.37 Billion
The Andromeda Galaxy Is Clearly Visible 1.37 Billion Years in the Future

2.06 Billion
2.06 Billion Years in the Future, Andromeda Dominates the Night Sky

3.49 Billion
3.49 Billion Years in the Future, Andromeda Dominates the Night Sky

3.78 Billion
Tidal Disruption Begins to Distort the Galaxies at 3.78 Billion Years

3.86 Billion
With Tidal Disruption Comes a Massive Outburst of Star Formation

3.98 Billion
Massive Distortion of Both Galaxies Occurs as They Pass Around 3.98 Billion Years

4.60 Billion
Star Formation has Begun on a Massive Scale 4.60 Billion Years

5.83 Billion
After Another Billion Years, Massive Stars Have Gone Nova

7.00 Billion
The Two Central Regions of the Galaxies Have Coalesced into an Elliptical Galaxy

Hubble Space Telescope: 22 Years Young

Doradus 30
Hubble Composite Image of the Star Forming Region in the Tarantula Nebula
Image Credit: NASA, ESA, D. Lennon and E. Sabbi (ESA/STScI), J. Anderson, S. E. de Mink, R. van der Marel, T. Sohn, and N. Walborn (STScI), N. Bastian (Excellence Cluster, Munich), L. Bedin (INAF, Padua), E. Bressert (ESO), P. Crowther (University of Sheffield), A. de Koter (University of Amsterdam), C. Evans (UKATC/STFC, Edinburgh), A. Herrero (IAC, Tenerife), N. Langer (AifA, Bonn), I. Platais (JHU), and H. Sana (University of Amsterdam)

Launched on 24 April 1990, the Hubble Space Telescope has provided many extraordinary images of the universe (Eagle Nebula, Antennae Galaxies, Asteroid Collision).

In celebration of the 22nd Anniversary, astronomers have released this image of the Tarantula Nebula (30 Doradus, or NGC 2070) in the Large Magellanic Cloud.

This is an intense star forming region containing several million stars ranging in age from several thousand years to 25 million years old. The image is approximately 650 light-years across.

Eagle Nebula – Multi Spectra View

The Eagle Nebula, also known as Messier-16 or NGC 6611, is a nebula visible in the Southern Hemisphere. This three color image was taken by the Wide-Field Imager camera on the MPG/ESO 2.2-meter telescope at the La Silla Observatory. One easily sees the Eagle, and at the heart of the Eagle are the Pillars of Creation.

ISO Eagle
The Eagle Nebula – Messier-16 – European Southern Observatory
Image Credit: ESO

The Hubble Space Telescope imprinted the Eagle Nebula in the public’s mind in 1995 with the publication of the Pillars of Creation. The Pillars can be seen above in the middle of the lower third of the image. Hubble’s image (below) stands the pillars on end, whereas the ESO image shows them tilted over toward the right.

Pillars of Creation
The Pillars of Creation in the Eagle Nebula –
Image Credit: NASA / ESA / STScI, Hester & Scowen (Arizona State University)

In this composite image (above) of the Pillars’ star forming regions, the tallest pillar is about four (4) light years high. The images were observed using a combination of SII/H-alpha and OIII filters.

Other wavelengths allow us to see inside the gas clouds that surround these regions. Up to 1998, the ESA Infrared Space Observatory (ISO) was the most sensitive mid infrared telescope ever built. ISO observations (below) were performed at 7 microns and 15 microns, aiming to detect embedded sources in the pillars.

ISO Eagle
Pillars of Creation in the Eagle Nebula – 1998
Image Credit: ESA / ISO / Pilbratt et al.

Near-Infrared imaging by The 8.2m-diameter Very Large Telescope’s (VLT) ANTU telescope (below), enabled astronomers to better penetrate the dust that obscures the interior of the pillars. This has allowed researchers to investigate the ‘evaporating gaseous globules’ (EGGs) first detected in the Hubble images. It looks like eleven (11) of these EEGs probably contained new stars. One can also see stars in the tips of the pillars.

ANTU Eagle
Pillars of Creation in the Eagle Nebula visualized by the ANTU Telescope
Image Credit: Credits: VLT/ISAAC/McCaughrean & Andersen/AIP/ESO

Recently, new images of the Eagle Nebula (below) in the far-infrared and sub-millimeter part of the spectrum have been release by the Herschel Infrared Observatory.


The Eagle Nebula by the Herschel Observatory
Image Credit: ESA /Herschel / PACS / SPIRE / Hill, Motte, HOBYS Key Programme Consortium

The image is color coded. 70 micron radiation is in blue and 160 microns in green from the Photodetector Array Camera (PACS). Red codes for 250 micron emissions using the Spectral and Photometric Imaging Receiver (SPIRE). The image shows the temperature of the dust, which ranges from 10 degrees Kelvin (above absolute zero) to 40 degrees Kelvin.

Herschel operates from a Lissajous orbit around the second Lagrangian point of the Sun–Earth system (L2), a virtual point located 1.5 million km from Earth in the direction opposite to the Sun.

The X-Ray image below was taken by the XMM-Newton Observatory, which was launched in 1999. The image is color coded for the different energy levels observed: red: 0.3–1 keV, green: 1–2 keV and blue: 2–8 keV.

XMM-Newton Eagle
X-Ray Sources in the The Eagle Nebula – XMM-Newton Observatory
Image Credit: ESA / XMM-Newton / EPIC / XMM-Newton-SOC / Boulanger

Researchers are investigating a theory that the Eagle Nebula is being powered by a hidden supernova remnant. They are trying to detect a faint X-ray emission in the nebula. If no emission is found beyond what the Chandra and Spitzer Observatories have already detected, this would support the supernova remnant theory.

A composite image from Herschel and XMM-Newton is shown below:

Composite Eagle
Composite Far-Infrared and X-Ray Sources in the The Eagle Nebula
Credits: far-infrared: ESA/Herschel/PACS/SPIRE/Hill, Motte, HOBYS Key Programme Consortium; X-ray: ESA/XMM-Newton/EPIC/XMM-Newton-SOC/Boulanger

Hanny’s Voorwerp

Hanny's Voorwerp

Original Galaxy Zoo image
of Hanny’s Voorwerp from the
Sloan Digital Sky Survey (SDSS) 2007
Image Credit: Galaxy Zoo

Dutch schoolteacher Hanny van Arkel, discovered the strange green “voorwerp” (Dutch for “object”) in 2007 while working on the Galaxy Zoo Project. Today, she presented the Hubble image seen below at the AAS meeting in Seattle.

The Hubble Site press release comments that:

Galaxy Zoo enlists the public to help classify more than a million galaxies cataloged in the Sloan Digital Sky Survey. The project has expanded to include the Hubble Zoo, in which the public is asked to assess tens of thousands of galaxies in deep imagery from the Hubble Space Telescope.

The object is located near IC 2497, a spiral galaxy about 700 million light years from the Earth.

It appears that the giant galaxy began tidally shredding a dwarf galaxy a billion years ago. The result is a trail of stars, gas and dust extending from IC 2497. At the end of this 300-light-year-long gaseous streamer is Hanny’s Voorwerp.

What makes the situation unusual is that the process of shredding the dwarf galaxy fed the quasar at the heart of IC 2497, spewing intense ultraviolet light and X-rays. These bombarded the Voorwerp and heated the gas.

The quasar turned off, apparently quite suddenly, between 70,000 and 100,000 years ago. The green color is attributed to glowing oxygen energized by the now quiet quasar.

Hanny's Voorwerp

Hanny’s Voorwerp in the green band of SDSS
Image Credit: Galaxy Zoo / ING

The Hubble Space Telescope image below from the Wide Field Camera 3 and Advanced Camera for Surveys, shows the yellow and orange star forming region in the upper right portion of the Voorwerp. Observations show that the quasar’s beam caused the collapse of the region and triggered the star formation, the youngest of which are only several million years old.

Professor William C. Keel is a member of the Galaxy Zoo team and leader of the Hubble study. He teaches at the University of Alabama. Keel notes:

The star clusters are localized, confined to an area that is over a few thousand light-years wide. The region may have been churning out stars for several million years. They are so dim that they have previously been lost in the brilliant light of the surrounding gas.

What we’re seeing is the afterglow from the quasar. This implies that it might flicker on and off, which is typical of quasars, but we’ve never seen such a dramatic change happen so rapidly.

Radio astronomy shows that the green pod of gas is part of a large structure that wraps around the nearby spiral galaxy. The Voorwerp is the only optically visible portion of this structure.

Hanny's Voorwerp
Hanny’s Voorwerp from the Hubble Space Telescope
Image Credit: NASA / ESA / W. Keel (University of Alabama), and the Galaxy Zoo team.