Category Archives: Galaxies

The first detection of an electromagnetic counterpart to a gravitational wave event

Full AAO Media Release, published at 01:00am Sydney time, 17 October 2017, that I coordinated.

For the first time, astronomers have observed the afterglow of an event that was also detected in gravitational waves. The object, dubbed AT2017gfo, was a pair of in-spiralling neutron stars in a galaxy 130 million light years away. The death spiral was detected in gravitational waves, and the resulting explosion was followed by over 50 observatories world wide, including the AAO and other observatories here in Australia.

On August 17, the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO), based in the United States, detected a new gravitational wave event, called GW170817.

GW170817 is the fifth source of gravitational waves ever recorded. The first one was discovered in September 2015, for which three founding members of the LIGO collaboration were awarded the 2017 Nobel Prize in Physics.

The GW170817 data are consistent with the merging of two neutron stars and are unlike the four previous events, which were merging black holes.

Artist’s illustration of two merging neutron stars. The narrow beams represent the gamma-ray burst while the rippling space-time grid indicates the gravitational waves that characterize the merger. Swirling clouds of material ejected from the merging stars are a possible source of the light that was seen at lower energies. Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonnet.

The Advanced-Virgo interferometer, based in Italy, was online at the time of the discovery and contributed to the localization of the new gravitational wave burst.

Based on information from LIGO and VIRGO, numerous telescopes immediately sprang into action to determine if an electromagnetic counterpart to the gravitational waves could be detected.

Meanwhile, NASA’s Fermi satellite independently reported a short burst of gamma-rays within 2 seconds of the merger event associated with GW170817, consistent with the area of sky from which LIGO and VIRGO detected their gravitational waves.

This gamma-ray detection at the same time and place triggered even greater interest from the astronomical community and resulted in more intense follow up observations in optical, infrared and radio wavelengths.

A team of scientists within the Dark Energy Survey (DES) collaboration, which includes researchers from the Australian Astronomical Observatory and other Australian institutions, working with astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) in the U.S., were among the first astronomers to observe the electromagnetic counterpart of GW170817 in optical wavelengths.

Using the 570-megapixel Dark Energy Camera (DECam) mounted at the 4m Blanco Telescope at Cerro Tololo Inter-American Observatory in Chile, DES identified the kilonova AT2017gfo in the nearby galaxy NGC 4993, located only 130 million light years from us, as the optical counterpart of GW170817.

Composite of detection images, including the discovery z image taken on August 18th and the g and r images taken 1 day later. Right: The same area two weeks later. Credit: Soares-Santos et al. and DES Collaboration.

“Because of its large field of view, the Dark Energy Camera was able to search almost the entire region where LIGO/VIRGO expected the gravitational wave source to be, and its exquisite sensitivity allowed us to make detailed measurements of the kilonova – the extremely energetic outburst created by the merging neutron stars,” AAO Instrument Scientist and DES Collaboration member Dr Kyler Kuehn stated.

A kilonova is similar to a supernova in some aspects, but it is different in others. It occurs when two neutron stars crash into each other. These events are thought to be the mechanism by which many of the elements heavier than iron, such as gold, are formed.

“But as impressive as it is, the Dark Energy Camera is only one of many instruments with a front row seat to this celestial spectacle. A lot of effort has gone into preparing dozens of telescopes around the world to search for electromagnetic counterparts to gravitational waves”, Dr Kuehn added.

Simultaneously to the DES study, a large group of Australian astronomers obtained follow up observations of the kilonova AT2017gfo at optical, infrared and radio wavelengths, using 14 Australian telescopes as part of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) and other Australian programs.

Their data are consistent with the expected outburst and subsequent merger of two neutron stars, in agreement with the results derived for GW170817 by the LIGO/Virgo collaboration.

“Before this event, it was like we were sitting in an IMAX theatre with blindfolds on. The gravitational wave detectors let us ‘hear’ the movies of black hole collisions, but we couldn’t see anything. This event lifted the blindfolds and, wow, what an amazing show!!”, A/Professor Jeff Cooke, astronomer at Swinburne University who led many of the observations said.

The Australia team also conducted observations at the 3.9m Anglo-Australian Telescope (AAT), that is managed by the Australian Astronomical Observatory (AAO). Additional archive data from the 6dF survey obtained at the AAO’s 1.2m UK Schmidt Telescope were also used.

“The observations undertaken at the AAT place important constraints on the nature of the environment in which the kilonova occurred”, AAO astronomer Dr Chris Lidman said.

The follow up observations were not scheduled, but the excitement that this event generated in the astronomical community was so large that regular programs were placed on hold.

“Many astronomers dropped any other planned observation and used all the available resources to study this rare event”, said PhD candidate Igor Andreoni (Swinburne University and Australian Astronomical Observatory), first author of the scientific paper that will be published in the science journal “Publications of the Astronomical Society of Australia” (PASA).

The study also reveals that the host galaxy has not experienced significant star-formation during the last billion years. However, there is some evidence that indicates that NGC 4993 experienced a collision with a smaller galaxy not long time ago.

The position of the kilonova AT2017gfo, found in the external parts of NGC 4993, may suggest that the binary neutron star could have been part of the smaller galaxy.

Australian astronomers were thrilled to contribute to both the detection and the ongoing observations of the kilonova AT2017gfo, the electromagnetic counterpart to the gravitational wave event GW170817.

“We have been waiting and preparing for an event like this, but didn’t think it would happen so soon and in a galaxy that is so near to us. Once we were alerted of the gravitational wave detection, we immediately contacted a dozen telescopes and joined the worldwide effort to study this historic event. It didn’t let us down!”, A/Professor Jeff Cooke said.

“It was crucial to have telescopes placed in every continent, including Australia, to keep this rare event continuously monitored”, PhD candidate Igor Andreoni said.

“To me, this gravitational + electromagnetic wave combined detection is even more important than the initial detection that resulted in the Nobel Prize. This has changed the way the entire astronomical community operates”, AAO Instrument Scientist Dr Kyler Kuehn stated.

The first identification of the electromagnetic counterpart to a gravitational wave event is a milestone in the history of modern Astronomy, and opens a new era of multi-messenger astronomy.

More information:

AAO Media Release

AAO Media Release in Spanish / Nota de prensa del AAO en español

LIGO Media Release

DES Media Release

OzGrav Media Release

ESO Media Release

NASA Media Release

Article in The Conversation: “After the alert: radio ‘eyes’ hunt the source of the gravitational waves”, by Tara Murphy and David Kaplan

Article in The Conversation: “At last, we’ve found gravitational waves from a collapsing pair of neutron stars”, by David Blair

Multimedia, videos and animations:

Although there are many videos around there talking about this huge announcement, I particularly like this one by Derek Muller (Veritasium):

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Image

Multiwavelength image of the spiral galaxy M 101

Multiwavelength image of nearby spiral galaxy M 101 combining ultraviolet (light blue), optical (green), near infrared (yellow), H-alpha and 8 microns mid-infrared (red) and 21 cm HI emission (dark blue). Each colour prepresents an important component of the galaxy: massive stars (light blue), stars (green and yellow), star-forming gas and dust (red) and neutral hydrogen (dark blue)

Compare with the Astronomical Picture of the Day on 13 July 2012 apod.nasa.gov/apod/ap120713.html

Data credit: UV data (GALEX): Gil de Paz et al. 2007, ApJS, 173, 185; R and Hα data (KPNO): Hoopes et al. 2001, ApJ, 559, 878; Near-Infrared data (2MASS): Jarrett et al. 2003, AJ, 125, 525, 8 microns data (Spitzer): Dale et al. 2009, ApJ, 703, 517; 21cm HI data (VLA): Walter et al. 2008, AJ, 136, 2563, ”The H I Nearby Galaxy Survey”.

Credit of the composition: Ángel R. López-Sánchez (AAO/MQ).

More sizes and high resolution image in My Flickr.

Podcast in FBI radio: The Milky Way is missing

Some few months ago I was interviewed by Zacha Rosen in the FBi’s Not What You Think radio show. I was talking about what a galaxy is, the feeling of seeing the center of the Milky Way close to the zenith for the first time, and the problem of the light pollution.

Radio interview in FBI Sydney

The show was broadcasted on FBI 94.5 FM at 10:30am Saturday October 22nd, Sydney time. It is also available as podcast from the Not What You Think webpage or using iTunes.

You can also listen to the 18 minutes interview here:

 

Thanks Zacha for this wonderful experience I hope to repeat in the future!

Video of the “Story of Light” in Vivid Sydney 2016

Following the success of our sold-out Event “The Story of Light – The Astronomer’s Perspective” for ViVID Sydney Ideas 2015, the Australian Astronomical Observatory (AAO) continued its collaboration with ViVID Sydney 2016 organizing “The Story of Light – Deciphering the data encoded on the cosmic light”. But actually it was me who was in charge of the organization.

The five astronomers speaking during our “Sydney Vivid Ideas: The Story of Light” started at the Powerhouse Museum, Sydney, 29th May 2016. From left to right: Luke Barnes, Alan Duffy, Vanessa Moss, Liz Mannering and Ángel López-Sánchez. Photo credit: Jenny Ghabache (AAO).

The event was held at the PowerHouse Museum in Sydney on Sunday 29th May 2016. More than 160 people attended this special event. Five young astronomers (me included) talked about Astronomy and Big Data: the light and light-based technologies developed in Australian astronomy for both optical and radio telescopes; the tools, platforms, and techniques used for data analysis and visualization; how astronomers create simulation data; how some of these techniques are being used in other research areas; and the major scientific contributions toward our understanding of the Universe. Indeed, astronomers have been pioneers in developing “Data Science” techniques to make sense of this huge data deluge, many of which are now used in other areas.

We recorded all the event in video, and it is now publicly available  in the AAO YouTube channel. Some photos of the event are also compiled below. I want to thank AAO/ITSO Research Astronomer Caroline Foster for helping recording and editing the video and Jenny Ghabache (AAO) for taking the photos of the event.

Full recording of the event “The Story of Light 2016: Deciphering the data encoded on the cosmic light” organised by the AAO for Vivid Sydney Ideas 2016. Credit: AAO. Acknowledgment: Caroline Foster (AAO).

The event was hosted by Alan Duffy (Swinburne University). I was in charge of explaining optical astronomy, the AAO, optical surveys and big data. Then my colleagues  Vanessa Moss (Univ of Sydney/CAASTRO), Luke Barnes (Univ. of Sydney) and Liz Mannering (AAO/ICRAR) discussed radio astronomy, the ASKAP and big data (Vanessa), simulating, analysing and visualizing astronomy data (Luke) and astronomy data archive, the All-Sky Virtual Observatory (ASVO) and other virtual observatories (Liz ). After the short 12-15 minutes talks (well, as usual I took a bit more time), the panel welcomed questions from the audience (and even from Twitter using #SoLSydneyIdeas) for a discussion session about Light and Astronomy and the Australian contribution to the improvement of our understanding of the Universe.

The Lecture Theatre a few minutes before our “Sydney Vivid Ideas: The Story of Light” started at the Powerhouse Museum, Sydney, 29th May 2016. Photo credit: Jenny Ghabache (AAO).

Our host, Alan Duffy, introducing the event. Photo credit: Jenny Ghabache (AAO).

AAO/MQU Research Astronomer Ángel R. López-Sánchez talking about optical astronomy, the AAO and big data. Photo credit: Jenny Ghabache (AAO).

Vanessa Moss (Univ. of Sydney/CAASTRO) talking about radioastronomy, the ASKAP and big data. Photo credit: Jenny Ghabache (AAO).

Luke Barnes (Univ. of Sydney) talking about simulating, analysing and visualizing astronomy data. Photo credit: Jenny Ghabache (AAO).

Liz Mannering (Univ. of Sydney) discussed astronomy data archive, the All-Sky Virtual Observatory (ASVO) and other virtual observatories. Photo credit: Jenny Ghabache (AAO).

Panel discussion with all participants answering questions from the audience. Photo credit: Jenny Ghabache (AAO).

Angel Lopez-Sanchez answering a question from the audience. Photo credit: Jenny Ghabache (AAO).

And last… Well, if you want to see only my talk, here it is:

Citizen scientists discover huge galaxy cluster

One of the scientific projects I’m involved actually is a citizen science program: Radio Galaxy Zoo. Using images from NASA’s Wide-Field Infrared Survey Explorer telescope (WISE) and the NRAO Very Large Array (VLA) in New Mexico, USA,  Radio Galaxy Zoo requests participants to associate radio emission (which is related to the relativistic electrons ejected from a massive black hole) with galaxies as seen in infrared light. The aim is to get a better understanding of the super-massive black holes that are located in the center of the galaxies and quantify their importance in galaxy evolution.

My colleagues Julie Banfield (Australian National University) and Ivy Wong  (ICRAR and University of Western Australia) lead the Radio Galaxy Zoo (RGZ) team, that was launched on December 2013. Since then, more than 10,000 volunteers have joined in with Radio Galaxy Zoo, classifying over 1.6 million images.

The wide-angle tail galaxy discovered by Terentev and Matorny is one of the largest known, and its host cluster is now known as the Matorny-Terentev cluster. Credit: Radio Galaxy Zoo.

The wide-angle tail galaxy discovered by Terentev and Matorny is one of the largest known, and its host cluster is now known as the Matorny-Terentev cluster. Credit: Radio Galaxy Zoo.

Well, the news is that two RGZ volunteer participants from Russia, Ivan Terentev and Tim Matorny, have discovered a rare galaxy cluster. They found that one particular radio-source had just one of a line of radio blobs that delineate a C-shaped “wide angle tail galaxy” (WAT). The C-shaped was formed because the massive galaxy hosting the super-massive black hole and its associated jets are moving through intergalactic gas, indicating the existence of a cluster of galaxies. The new wide-angle tail galaxy is one of the largest known, and its host cluster is now known as the Matorny-Terentev cluster.

The details of this discovery has been published this week in the prestigious scientific journal MNRAS, the paper “Radio Galaxy Zoo: discovery of a poor cluster through a giant wide-angle tail radio galaxy” was lead by Julie Banfield (ANU).

There is plenty of information in the Radio Galaxy Zoo webpage, the  CAASTRO Press Release and in this nice Article in “The Conversation” by Ray Norris (CSIRO/Western Sydney University and PI of the EMU project to be conducted in the ASKAP), so I’ll just add here the nice interview to Ivy Wong  (ICRAR and University of Western Australia) in Ten News Australia yesterday.

More information:

A year since the “Multiwavelength Dissection of Galaxies” Conference

I cannot believe a FULL YEAR has already gone since the “Multiwavelength Dissection of Galaxies” Conference happened. And I have never found the time to just describe how much work this was for me, and at the success of this meeting. At least let me share today the article I wrote for “The Observer”, the AAO Newsletter.

 
The Southern Cross Astrophysics Conferences, which are jointly supported by the Australian Astronomical Observatory (AAO) and the CSIRO Astronomy and Space Science (CASS), are held annually around Australia with the aim of attracting international experts with wide ranging skills to discuss a particular astrophysical topic. The conference “Multiwavelength dissection of galaxies”, which was held at the Crown Plaza Hotel in  Coogee Beach, Sydney between 24th – 29th May 2015, was the 8th of the Southern Cross Conference Series. This Conference focused on galaxy evolution, combining resolved optical/near-infrared integral field spectroscopy data with other multiwavelength properties (from X-ray to radio) of nearby galaxies plus giving the view of what is known in our Milky Way.

Poster of the Conference "Multiwavelength Dissection of Galaxies".

Poster of the Conference “Multiwavelength Dissection of Galaxies”.

Indeed, the number of studies of galaxies using integral field spectroscopy (IFS) is rapidly increasing as a consequence of surveys such as ATLAS-3D, CALIFA, SAMI (that is conducted at the AAT), or MANGA. IFS techniques allow to spatially resolve internal properties of galaxies with unprecedented detail, and therefore they are providing key clues for understanding the structural components of galaxies, their star-formation activity, kinematics, stellar populations, metal distribution, and nuclear activity, as well as how galaxies evolve with time. Nevertheless, for a complete picture of how galaxies work it is crucial to use other multi-wavelength results, targeting galaxies in X-ray, ultraviolet, infrared, and radio frequencies. In particular, HI radio-surveys such as HIPASS, LVHIS, THINGS, Little-THINGS, ALFALFA, HALOGAS or WALLABY are essential to trace the neutral gas content of galaxies, as the 21 cm HI radio data provide key information about how the cold gas in converted into stars and galaxy dynamics. At the same time we are notably increasing our knowledge of the structure and composition of the Milky Way. This is possible thanks to the combination of very detailed observations of individual stars (such those coming from the RAVE survey conducted at the 1.2m UKST or the on-going GALAH survey at the AAT using the new high-resolution HERMES spectrograph), detailed analyses of Galactic nebulae, large field studies of the interstellar medium, and surveys searching for the diffuse gas with and around our Galaxy.

Hence, the aim of the “Multiwavelength dissection of galaxies” Conference was to bring together international experts in both Galactic and extragalactic astronomy to discuss the different components of a galaxy: stars, gas, dust, and dark matter, and where these components are found within and around galaxies, from both an observational (from radio to X-rays, but with a fundamental optical IFS component) and a theoretical point of view (from the most recent simulations of galaxy assembly to models reproducing the chemical evolution of galaxies), with the final objective of getting a better understanding on the processes that rule the evolution of the galaxies.

Conference Photo with the majority of the participants to the “Multiwavelength Dissection of Galaxies” meeting, 24th - 29th  May 2015. The background is an image of the Southern sky showing the Southern Cross and the Pointers. Credit: Conference Photo: Andy Green (AAO), Background image & composition: Ángel R. López-Sánchez.

Conference Photo with the majority of the participants to the “Multiwavelength Dissection of Galaxies” meeting, 24th – 29th May 2015. The background is an image of the Southern sky showing the Southern Cross and the Pointers. Credit: Conference Photo: Andy Green (AAO), Background image & composition: Ángel R. López-Sánchez.

Around 120 astronomers all around the globe attended to this Conference. In five days we had 94 talks, including 27 invited talks and a Summary talk, and 26 poster contributions. Highlight invited talks were given by Rosemary Wyse (The Structure of the Milky Way), Naomi McClure-Griffiths (Neutral gas in and around the Milky Way), Baerbel Koribalski (Diffuse gas in and around galaxies), Christy Tremonti (Measuring Gas Accretion and Outflow Signatures with MaNGA), César Esteban (Ionized gas in the Milky Way), Evan Skillman (The Chemical Properties of the ISM of Nearby Galaxies), Sarah Martell (Introduction to the GALAH Survey), Geraint Lewis (Galactic Archeology in the Local Group), Alessandro Boselli (The dust emission properties of nearby galaxies after Herschel), Jakob Walcher (News about the interstellar medium in galaxies from the CALIFA survey), Stas Shabala (Resolving the mysteries of AGN feedback:radio jets, galaxies and citizen science), Joss Bland-Hawthorn (Near Field Cosmology), Martin Asplund (The Gaia-ESO survey), Richard Bower (The EAGLE Universe), Lisa Kewley (SAMI Science) and Molly Peeples (A Multiwavelength View of the Circumgalactic Medium).

We also organised a “Poster Contest”: participants were asked to vote for their 2 favourite posters, and they got a short (10 minutes) talk during the last session of the Conference. The winners were two PhD students: Christina Baldwin (Macquarie University, Australia, with the poster “Early-Type Galaxy Stellar Populations in the Near-Infrared”) and Manuel Emilio Moreno-Raya (Universidad Complutense Madrid and CIEMAT, Spain, with the poster “Dependence of SNe Ia absolute magnitudes on the host galaxies elemental gas-phase abundances”).

We have compiled all scientific presentations at the Conference Webpage:

http://www.aao.gov.au/conference/multiwavelength-dissection-of-galaxies

Furthermore, participants were very active in Twitter, that followed the hashtag of the Conference #MDGal15, allowing a wider diffusion of the main results speakers were presenting. We have also compiled all tweets in a Storify for each day, they are available in our website.

Besides the scientific talks, participants enjoyed the social events we organised for the Conference, including a Welcome Cocktail Cruise on Sunday 24th May (delegates enjoyed not only the great views of Sydney Harbour but also a starry sky and the famous ViVID Lights Sydney Festival), a Wine Tasting event on Tuesday 26th, an outdoors barbecue and a visit to Sydney Observatory and Stargazing on Wednesday 27th May, and the Conference Dinner on Thursday 28th May, which was held at the Spanish restaurant “Postales” in famous Martin Place, Sydney. Furthermore, the AAO organised the Public Event “The Story of Light: The Astronomer’s Perspective” on Sunday 24th May at the Powerhouse Museum (Sydney). This event, which was fully booked, was included as part of the ViVID Festival and connected the International Year of Light 2015 with our Conference.

Overall, we considered it was a great Conference and some important and controversial research topics were actually discussed during those five days, generating new ideas and projects, and many new collaborations between participants (even between Galactic and extragalactic astronomers) started there.

Finally, I would like to thank the impeccable organisation of the staff at Crown Plaza Hotel, as everything worked very smoothly and we didn’t have any problems at all during our Conference. In particular, coffee breaks and lunches were very well attended, and we really enjoyed a great quality food. Of course, I also must thank all the members of the LOC and the SOC committees for their invaluable help organising this Conference. In particular, I would like to thank Helen Woods (AAO) for her enormous effort and Andrew Hopkins and AAO’s Director, Warrick Couch, for their strong support to this meeting.

Spiral galaxy NGC 4027 with AAT: an outreach exercise

During this week I’m curator of the @astrotweep, a Twitter account that each week features an astronomer or planetary scientist taking about their research, science and life. I’m having a lot of fun with it, although I have to recognize it is extra work.

I chose to do it this week because there are some few things happening. In particular, I’m supporting observations at the Anglo-Australian Telescope (Siding Spring Observatory, NSW, Australia) using the 2dF / HERMES instruments. I thought it would be nice to be tweeting life how observations are doing. And that is precisely what I’ve doing today.

On top of that, “this morning” I had an idea. As we always have some “free time” at the AAT after completing the “2dF first night setup” (1) I decided to observe a nice bright deep sky object and get a nice image with the AAT. I was starting to search for a suitable target, but then I though, why don’t I ask the public what do they want to observe?

After consulting with my supervisors and getting the OK to do this, I initiated a poll in both @astrotweeps and @AAOastro asking the public to vote for one of the four following astro objects:

  1. The elliptical galaxy NGC 2865.
  2. The planetary nebula NGC 4361.
  3. The warped and almost edge-on spiral galaxy ESO 510-G13.
  4. The barred spiral galaxy NGC 4027.

For around 8 hours people were casting their vote, we received 153 unique votes in total combining the @AAOastro and the @astrotweets accounts.

And the winner (2) was… the barred spiral galaxy NGC 4027!

But surprises didn’t end here. In the afternoon, when I was starting to prepare the instruments for the night (I’m conducting observations remotely from Sydney), I explained to astronomers and technicians at the AAT what we were doing. Rob Paterson, our afternoon technician, then told me “Do you know we already have the new CCD camera installed in 2dF and just waiting for testing it?

Let me explain why I was so excited when I heard this. For years the 2dF instrument has had an auxiliary camera, the FPI camera, that we use for properly positioning 2dF in the requested field. Rarely it has been used for science, as it is just a 516×516 pixels camera without filters. Occasionally I have also used it for getting some images of deep sky objects. But, as it has no filters, I had to get the color of the images elsewhere, usually taking archive data taken with other telescopes. But the new CCD camera in 2dF does have filters!

Rob phoned Steve Lee, the head of the Night Assistants at the AAT, and with Bob Dean the three of them managed to prepare CACTI (that is the name of the new camera) to have it ready for us.

Although there is still a lot to be done and tests to be conducted, the very first images I got this evening are quite promising. Here is the final result:

Spiral galaxy NGC 4027 located at around 75 million light years in Corvus (The Crow). This barred spiral galaxy, also identified as Arp 22, is identified as a peculiar galaxy by the extended arm, thought to be the result of a collision with another galaxy millions of years ago. This image is the “First Light” of the new CACTI camera in 2dF @ 3.9m Anglo-Australian Telescope. Color image using B (4 x 120 s, blue) + V (6 x 60 s, green) + R (6 x 60 s, red) filters. The data were taken on 11 May 2016 as part of an “outreach exercise” via social media. Click here to get a higher resolution image. Credit: Ángel R. López-Sánchez (AAO/MQ) & Steve Lee, Robert Paterson & Robert Dean (AAO). Night assistant at the AAT: Andre Phillips (AAO).

Note that this image, that actually is the “first light” of the CACTI camera, only combines 6 minutes in V and R and 8 minutes in B, that is, it is not deep at all. Furthermore not extra calibrations were taken (some flatfield images would have been nice). The deep image obtained by the 3.6m NTT telescope (ESO La Silla Observatory, Chile) provides many more details and resolution… but of course they were using the EFOSC instrument, which was specifically designed for deep imaging in optical filters. And the  image of NGC 4027 obtained by David Malin (AAO) using photographic plates at the AAT in 1982 is much more colorful.

But I still think it is a pretty result, particularly as this new image of NGC 4027 was obtained as a completely improvised “outreach exercise” using social media, in which 153 people voted for their favorite object to be observed at the 3.9m Anglo-Australian Telescope.

I really hope to repeat this exercise soon.

(1) A 2dF Plate must be configured with a scientific field, that is, allocating ~350 optical fibres to different objects in the sky. This takes ~ 20-30 minutes.

(2) Just to provide the details of the votes, see table below:

OBJECT    @Astrotweeps   @AAOastro       COMBINED

NGC 2865               5                  4                    9    ( 6% )

NGC 4361            36                   9                   45   (29%)

ESO 510-G13      36                  7                     43   (28%)

NGC 4027           36                20                    56   (37%)

TOTAL              113                 40                   153