Tag Archives: stars

Measure the light pollution in your street this Sunday

My “SpaceNews” for the episode of “The Skyentists” that Kirsten and me released yesterday was to talk about the citizen science project that is running this Sunday, 21st June (Winter Solstice in the Southern Hemisphere) with the aims of measure the light pollution in Australia and New Zealand.

You have all the information about the event on the webpage of the Australasian Dark Sky Alliance, and PLEASE do register to participe on it. It is very easy and fun to do: just observe the sky with your unaided eye and estimate how many stars do you see using the Globe at Night Web App.

This citizen science project is also part of the Guinness World Records ™ Official Attempt for Most users to take an online environmental sustainability lesson in 24 hours.

As you know, I’ve been fighting the big problem of the light pollution for decades, and not only because it negatively affects us, astronomers, but also because of the huge environmental impact that the light pollution is, with plenty of negative effects in flora, fauna and our health, and on top of that it is a stupid way of wasting our resources (and MONEY) and contribute to CO2 emission.

Hence, I’m helping as much as I can to promote this citizen science project and make the people aware of what we are missing because we are not illuminating properly our cities.

Science in Public has prepared a media release about it, and I have contributed with several of my astronomical images and timelapses.

This morning, Marnie Ogg, CEO of the Australasian Dark Sky Alliance, has been interviewed by the famous weather presenter, meteorologist and science communicator Nate Byrne in the public Australian TV channel, ABC, about it.

https://platform.twitter.com/widgets.js

And I’m very happy because, for some few seconds, I was on TV!!!

I’m very grateful to Niall Byrne (Science in Public), Tanya HaNate Byrne and Marnie Ogg for using my images and videos for all of this, but also for crediting them.

So, now you know, this Sunday evening don’t stay inside your house: get your kids, your friends, your family, your parents, your boyfriend or your girlfriend and look at the sky to help us measuring the light pollution in Australia, and perhaps even beating a World Guinness Record!

Update: Below I compile the links to articles in the media that have used my images for talking about all of this.

  1. Longest night, darkest sky, COSMOS, 17 June 2020.
  2. Look up! Help find the darkest sky, Gazette, 19 June 2020.
  3. Count the stars in the Southern Cross during winter solstice and map light pollution in your suburb, in ABC News, 19 June 2020.
  4. Stargazing to aid light pollution research, The Young Witness, 19 June 2020 (Photo NOT credited).
  5. Light pollution to be mapped during winter solstice on Sunday, Queensland Country Life, 19 June 2020.
  6. Light pollution is bad for us and for wildlife. So what can we do to solve the problem? in ABC News, 20 June 2020.
  7. Winter solstice 2020: Australia has a chance to break a stargazing record, The Guardian, 21 June 2020
  8. Help measure who has the darkest skies in Australia, The Canberra Times, 21 June 2020.
  9. Help measure who has the darkest skies in Australia, The Land, 21 June 2020.
  10. Can you see the stars? Who has the darkest skies?, Clarence Valley Independent, 21 June 2020.
  11. We can all be stargazers – and now is the perfect time to start, Clarence Valley Independent, 21 June 2020.
  12. Help measure who has the darkest skies in Australia, The Rural, 21 June 2020. (The same article has been published in a total of 33 newspapers!!! I’m not going to list all of those here, some of them are: Illawarra, Central Western Daily, Mudgee Guardian, Hunter Valley News, Bendigo, Glen Innes Examiner, Wauchope Gazette, Moree, Barossa Herald, Margaret River Mail, Walcha News, South Coast Register, Sunshine Coast Daily, Busselton Mail…)

#WomeninSTEM: Book “The Glass Universe”

Today, 11th February, we’re celebrating the International Day of Women and Girls in Science. Introduced by the UN in December 2015, this is the second year it is done. This International Day recognizes the critical role women and girls play in science and technology communities, and aims to promote events that support and promote the access of women and girls and their participation in science, technology, engineering and mathematics education, training and research activities at all levels.

For this I really recommend the wonderful new book by famous science writer Dava Sobel: The Glass Universe. This book describes the challenges and achievements at Harvard College Observatory (U.S.A.), when in the mid-nineteenth century began employing women as calculators, or “human computers”, to interpret the observations their male counterparts made via telescope each night. Observations were taken with the new technique of photography.

In particular, they used glass photographic plates (in few decades they got almost half a million of them!) and, as “readers of books written in glass”, these women made extraordinary discoveries that definitively changed the way we understood the stars and the Universe. They helped discern what the stars were made of, divided them into meaningful categories for further research, and even found a way to measure distances across space by starlight. The lifes and works of all these women are truly inspiring.

Book "The Glass Universe" by Dava Sobel. Wonderful.

Book “The Glass Universe” by Dava Sobel. Wonderful.

I’m still half way through the book, but I’ll update this post during the week providing extra information about what I’ve found most fascinating on it. Believe me I’m finding many discoveries reading  “The Glass Universe“, starting with realizing how “reading the lines of the stars” (spectroscopy) was done in those times.

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:

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.

The oldest stars of the Galaxy

DP ENGLISH: This story belongs to the series “Double Post” which indicates posts that have been written both in English in The Lined Wolf and in Spanish in El Lobo Rayado.

DP ESPAÑOL: Esta historia entra en la categoría “Doble Post” donde indico artículos que han sido escritos tanto en español en El Lobo Rayado como en inglés en The Lined Wolf.

Last month the prestigious journal Nature published a letter led by PhD student (and friend) Louise Howes (@Lousie, ANU/RSAA, Australia). This scientific paper, with title Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way, uses data from the 1.2m Skymapper Telescope, the 3.9m Anglo-Australian Telescope (both at Siding Spring Observatory, NSW, Australia) and the 6.5m Magellan Clay telescope (Las Campanas Observatory, Chile) to study very old stars in the Milky Way bulge.

Image of the Galactic centre obtained using Skymapper data. Credit: Chris Owen (ANU/RSAA).

Image of the Galactic centre obtained using Skymapper data. Credit: Chris Owen (ANU/RSAA).

The aim of the research was to look for signatures of really old stars: stars that old that perhaps the Milky Was was not even born when they were created! How do astronomers know that? Just studying the chemical composition of the stars via deep spectral analysis. Only hydrogen and helium (and just a bit of litium) were formed in the Big Bang: the rest of elements have been created or inside the stars (oxygen, carbon, nitrogen, iron) or because of processes happening to the stars (e.g., supernova explosions, that create heavy elements such as gold, silver, copper or uranium). As time goes by and new generations of stars are born, the amount of metals (for astronomers, metals are all elements which are not hydrogen and helium) increases. Therefore if we discover a star with very few amount of metals, we will quite sure we are observing a very old object.

Loiuse has been using the 2dF instrument at the Anglo-Australian Telescope and the MIKE spectrograph at the Magellan Clay Telescope (Chile) to get deep, high-resolution spectra of candidate old stars in the Galactic bulge. The candidate stars were identified using optical images provided by the 1.2m Skymapper Telescope. With these observations, Louise Howes and collaborators have detected 23 stars that are extremely metal-poor. These stars have surprisingly low levels of carbon, iron and other heavy elements. Indeed, they report the discovery of a star that has an abundance of iron which is 10,000 times lower than that found in the Sun! These stars were formed at redshift greater than 15, that is, we are observing in our own Milky Way stars that were formed just ~300 million years after the Big Bang!

On top of that, the study suggests that these first stars didn’t explode as normal supernova but as hypernova: poorly understood explosions of probably rapidly rotating stars producing 10 times as much energy as normal supernovae. The high-resolution spectroscopic data have been also used to study the kinematics of these very old stars, that are found on tight orbits around the Galactic centre rather that being halo stars passing through the bulge. This is also characteristic of stars that were formed at redshifts greater than 15.

Short 3 minutes video discussing the results found in this study. Credit: ANU.

I’m happy to say here that I’ve been the support astronomer for many of her nights at the AAT the last couple of years. And I’m extremely happy to see that, even because of the bad weather we have had sometimes, they managed to get these observations published in Nature! Well done, Louise!

More details:

Scientific paper in Nature: Howes et al. 2015, Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way, 11 November 2015.

Scientific paper in arXiv

ANU Press Release