The RASNZ Email newsletter is distributed by email on or near the 20th of each month. If you would like to be on the circulation list This email address is being protected from spambots. You need JavaScript enabled to view it. for a copy.

Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website http://www.rasnz.org.nz/ in their own newsletters provided an acknowledgement of the source is also included.

Contents

1. Steve Kerr to Direct the Occultation Section
2. ATV-5 Shallow Re-entry Cancelled
3. Notice of AGM
4. Notice of a Meeting of the Affiliated Societies Committee
5. Internet Continuing Education - Variable Stars
6. The Solar System in March
7. 2015 RASNZ Conference
8. 9th Trans-Tasman Symposium on Occultations (TTSO9)
9. 2017 Conference - Host Sought
10. Eta Carinae's Stars Clash
11. Inflation Signature Not Found in Plank Analysis
12. How to Join RASNZ
13. Gifford-Eiby Lecture Fund
14. Quote

1. Steve Kerr to Direct the Occultation Section

The RASNZ Council has appointed Steve Kerr be the Director of the Occultation Section. Steve succeeds the late Graham Blow who founded the Section. By way of introduction Steve has provided the following biographical note.


I am an Industrial Chemist by training and profession working in the electricity generation industry and based at Rockhampton in central Queensland, Australia. I consider myself to have been an amateur astronomer since the age of 10 and my early mentors were involved in occultation observing and other forms of 'scientific' observational astronomy. My earliest formal contact with the RASNZ Occultation Section was in 1984 when I commenced timing the eclipse disappearance and reappearances of the Galilean satellites of Jupiter for Brian Loader as part of the program he was running for the Jet Propulsion Laboratory (JPL). I continued making these observations through until 1991.

It was not until the late 1990's (after finishing my Chemistry Degree and getting a job) that I made direct contact with Graham Blow and commenced making observations of other sorts of occultation phenomena - specifically lunar and asteroidal occultations. Graham almost immediately got me involved with the section's newly created website and for a number of years, I was responsible for all site updates and data management. This extended to preparing notes for the section circular relating to asteroidal occultations. Most of these activities (and in fact most astronomy in general) had to stop in 2001 when I became a parent.

Since then, my involvement in the RASNZ Occultation Section has been in: - active observer of asteroidal occultations with less emphasis on lunar occultations - attended all of the Trans-Tasman Symposia on Occultations (TTSO's) to date usually making presentations and acting as convenor for TTSO6 in Brisbane in 2012. - writing a semi-regular column for Australian Sky and Telescope on occultations with strong reference back to the RASNZ Section.

Beyond occultation astronomy, I have been an active variable star observer both for the RASNZ VSS under Dr Frank Bateson and more recently with Variable Stars South. I also operate a semi automatic video meteor observation program as part of the IMO (International Meteor Organisation) video observing program. I am a member of the AAQ (Astronomical Association of Queensland) and promote occultation observing within that organisation.

Graham Blow has often discussed Occultation Section matters when we caught up over the years - we first met face to face in 2003. I must say I was shocked and very humbled when he broke the news to me of his medical condition and that he was considering nominating myself as a possible next director for the Section. I fully realise that these are enormous shoes to fill but also that Graham has cultivated a very effective network of people across New Zealand and Australia that together make the Section's activities possible. This network of volunteers will be critical going in to the future. On that basis, I am prepared to take on the role of the Director should the Council see fit.

2. ATV-5 Shallow Re-entry Cancelled

Following the failure of one its systems the scheduled shallow re- entry of the International Space Station supply craft ATV-5, aka Georges Lemaitre, on 23 February has been cancelled. The shallow re- entry, crossing NZ, was intended as a test of the eventual de-orbiting of the ISS itself. (See Newsletter No.169, Item 3.) Instead ATV-5 was de-orbited on a standard steep re-entry around February 15. For background see http://blogs.esa.int/atv/2015/02/10/atvs-not-over-til-its-over/

3. Notice of AGM

The 92nd Annual General Meeting of the Royal Astronomical Society of New Zealand will be held at about 4:30 pm on Saturday the 9th of May 2015 in the Community Hall at Tekapo. Notices of Motion are invited and should reach the Executive Secretary six weeks in advance of the meeting, by 28 March 2015. They should be sent in writing to: R O'Keeffe Executive Secretary, RASNZ 662 Onewhero-Tuakau Bridge Rd RD 2 TUAKAU 2697

4. Notice of a Meeting of the Affiliated Societies Committee

The Affiliated Societies Committee will meet on Friday the 8th of May 2015 at the Community Hall in Tekapo. This meeting is normally attended by the Presidents of Affiliated Societies or their nominated representative. Notices of Motion for the meeting are invited and should reach the Executive Secretary by March 28, 2015. -- Rory O'Keeffe, Executive Secretary, RASNZ, 662 Onewhero-Tuakau Bridge Rd, RD 2, TUAKAU 2697

5. Internet Continuing Education - Variable Stars

The American Association of Variable Star Observers (AAVSO) has available internet based courses under the banner of the CHOICE (Carolyn Hurless Online Institute for Continuing Education in Astronomy) programme. These short courses cover topics such as variable star instrumental techniques, light curve analysis and star evolution. Those in the remainder of 2015 dealing with visual observing and star behaviour are: April 6 to May 1 Developing a Visual Observing Program April 6 to May 1 Variable Star Types and Light Curves July 6 to 31 Stellar Structure and Birth Aug 3 to 28 Stellar Evolution and Death Sept 7 to Oct 2 Variable Star Types and Light Curves

For courses on instrumental techniques and courses later in the year see the full list on the web site, which includes a course prescription for each item. http://www.aavso.org/2015-choice-course-schedule

General Information: The courses are generally of four to six weeks duration and it is suggested the time commitment is 8 to 20 h/week. The sessions may involve group discussions, quizzes, assignments and or a test. Cost per course is $US50 (reduced cost for AAVSO members). For general information see http://www.aavso.org/choice-astronomy. Registration is via the AAVSO online store: http://www.aavso.org/aavso-online-store

-- Contributed by Alan Baldwin

6. The Solar System in March

All dates and times are NZDT (UT +13 hours) unless otherwise specified. Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.

SUNRISE, SUNSET and TWILIGHT TIMES in March                          
                       March  1                      March 31        
             morning       evening           morning       evening   
          rise: 6.58am,  set:  8.07pm     rise: 7.32am,  set:  7.17pm
Twilights                                                            
Civil:    starts: 6.33am, ends: 8.33pm  starts: 7.07am,  ends: 7.43pm
Nautical: starts: 5.59am, ends: 9.07pm  starts: 6.35am,  ends: 8.15pm
Astro:    starts: 5.23am, ends: 9.42pm  starts: 6.03am,  ends: 8.47pm
March PHASES OF THE MOON (times as shown by GUIDE)      
  Full moon:     March  6 at  7.05 am (Mar  5, 18:05 UT)
  Last quarter:  March 14 at  6.48 am (Mar 13, 17:48 UT)
  New moon:      March 20 at 10.36 pm (        09:36 UT)
  First quarter: March 27 at  8.43 pm (        07:43 UT)

The planets

Venus and Mars remain early evening objects, setting soon after the Sun. Jupiter, just past opposition, will be prominent all evening, Saturn rises late to mid evening so will be visible low to the east an hour later. Mercury is an easy morning object in the first part of March.

Mercury continues to be well placed for morning viewing before sunrise, during the first part of March. It rises more than 2 hours before the Sun on March 1st The planet will be 12° above the horizon in a direction a little to the south of east at the beginning of nautical twilight (Sun 12° below the horizon), about 6 am. At magnitude 0.0 the planet will be the brightest object low to the east.

Mercury starts March in Capricornus. As it moves to the east through the stars, it will pass the asteroid Vesta, magnitude 7.9, early in the month. The two are closest on the morning of March 5 when Vesta will be 50 arc-minutes to the upper right of Mercury. On that morning the star iota Cap, magnitude 4.3, will be 25 arc-minutes above Mercury with Vesta 40 arc minutes to the right of the star. They should be easy to pick up in binoculars while the sky is still nearly dark.

Mercury moves on into Aquarius on March 12 still rising 2 hours before the Sun and readily visible an hour before sunrise. A week later, on the morning of March 19, Mercury will rise only 100 minutes before the Sun, so making it lower in the morning sky at the equivalent time. The planet will be a little brighter at magnitude -0.3. On that morning Mercury will appear close to Neptune, the latter 1.6° to Mercury's left. At magnitude 8.0 Neptune will not be easy in binoculars. The moon will also be quite close, a very thin crescent some 5° to the two planets left and a little higher.

During the rest of the month Mercury will get lower in the morning sky. By the 31st it will rise less only 50 minutes before the Sun making it difficult to find even though now at magnitude -1.0.

Venus and MARS, together with Uranus, are all quite close in the early evening sky. But they will be low. On the 1st, half an hour after sunset, at the end of civil twilight, Venus will be 7.5° above the horizon, at magnitude -4.0 easy to find. Mars, much fainter, magnitude 1.3, will be a 3° left of, and slightly lower than Venus. It will need binoculars to locate. Uranus, fainter still at 5.9, will be 4° to the right of Venus and a little higher. But it is not likely to be visible even in binoculars.

On the 1st Mars will set just an hour after the Sun, Venus about 10 minutes later and Uranus just over 10 minutes later again.

As the month progresses the two inner planets will move past Uranus. Venus will be closest to Uranus on the 4th and 5th. On the 4th it will be to the lower left of Uranus, on the 5th to its upper right, the separation of the two planets being just over half a degree, the diameter of the full moon, on both nights. Mars passes Uranus on the 11th and 12th and will be slightly closer to Uranus than Venus was. By then, Mars will set less than 1 hour after the Sun, making it a difficult object - Uranus just about impossible!

By the end of March, Mars will be setting only 45 minutes after the Sun, but Venus on the other hand will set nearly 90 minutes later than the Sun, as its elongation from the Sun increases.

On the 22nd the 5% lit crescent moon will be just under 5° to the upper right of Mars. The following night, now 12% lit, will be just over 5°to the upper right of Venus.

Jupiter will be easily visible to the northeast by the time Venus is lost to view. It will remain in the sky until well after midnight. The planet is in Cancer, moving slowly to the west through the stars, its westerly motion being due to the faster moving Earth overtaking it.

Jupiter motion in Cancer is towards the Praesepe cluster. By the end of March they will be some 5° apart. Their separation won't get much less as Jupiter reverses direction early in April when it starts moving to the east again.

The moon passes Jupiter twice in March. On the 3rd the nearly full moon will be 5° from Jupiter. On the 30th the moon coming round for a second time will be about half a degree closer. It will then be 78% lit.

Mutual events of jovian satellites

There are about 27 mutual events of Jupiter's Galilean satellites observable from NZ during March. Now Jupiter is visible in the evening sky, some of these take place at a more convenient time. They include:

  • March 8, Ganymede occults Callisto mid event ca 10:38pm. The two merge about 10:20 and separate again about 10:55.
  • March 14, Io eclipses Ganymede. Maximum ecl just after 9 pm Starts ca 8:50, ends ca 9:10, mag change 0.5
  • March 15, Europa occults Io mid event 9:24 pm merge ca 9:20, separate ca 9:28
  • March 27, Io eclipses Europa. Maximum eclipse ca 8:56 pm Starts ca 8:53, ends ca 8:59, mag change 1.0 Europa will be only 13" from Jupiter's limb
  • March 31, Ganymede eclipses Europa. Maximum eclipse ca 10:22 pm Starts ca 10:18, end ca 10:26, mag change 0.5

Useful observations and timings of these events can be made by those set up for the video observation of minor planet occultations.

Users of Dave Herald's Occult program can generate their own predictions of these and other events. Hristo Pavlov's Occult Watcher programme will also list them and has diagrams showing the satellites relative to Jupiter. Details can also be found on the IMCCE web site, http://www.imcce.fr/phemu/ where predictions and requirements for observing and reporting information are available.

Saturn rises just before midnight on 1st March. By the 31st it will rise a little before 10 pm so getting about 4 minutes earlier each night. The planet is in Scorpius and is stationary mid-month. As a result the position of Saturn changes very little during the month. It will be less than 2° from the 2.6 magnitude double star beta Sco. The companion of beta has a magnitude 4.5 and is 14" from the brighter star. Binoculars will show up the star's double nature.

On the 12th the gibbous moon, 62% lit, will be 3.5° from Saturn, with the moon on the opposite side of Saturn to beta Sco. At midnight on the 12th, Saturn will be visible low in a directions a little south of east, having risen about an hour earlier.

At present Saturn's north pole is tilted 25° towards the Earth. This brings the northern surface of the rings well into view. They should be visible in binoculars, although a small telescope is likely to give a better view.

Outer planets

Uranus remains in Pisces in March, an evening object magnitude 5.9. It will set 80 minutes after the Sun on the 1st, but only 15 minutes later than the Sun on the 31st. So even at the beginning of the month it will be a difficult binocular object in the Sunset glow. The close approach of Venus on the 4th and 5th may make locating Uranus using binoculars easier

Neptune was at conjunction with the Sun on February 26. It becomes a morning object in March. By the 31st it rises 2 hours before the Sun. The planet is in Aquarius at magnitude 8.

Pluto is in Sagittarius rising near 2.30 am on the 1st and 2 hours earlier on the 31st. Its magnitude is 14.4

Brighter asteroids:

(1) Ceres is a morning object in Sagittarius with magnitude 9.2. On the 1st it will be just over 6° from Pluto and rise 4 minutes later. On the 31st Ceres crosses into Capricornus, it then rises about 1.20 am.

(3) Juno is an evening object in Cancer during March. It loses brightness steadily during the month as its distance from the Earth increases. Its magnitude ranges from 8.8 in the 1st to 9.6 on the 31st.

(4) Vesta is in Capricornus at the start of March. It moves into Aquarius on the 22nd. On the morning of the 16th it will be just over a quarter degree, half the diameter of the full moon, to the left of the star delta Cap, magnitude 2.9. This should make Vesta easy to locate in binoculars. About 6am would be a good time to look for the two. Don't confuse Vesta with an 8.8 magnitude star a little to its right.

(7) Iris is in Leo and at opposition at the beginning of the month. Its magnitude will then be 8.9. It moves into Sextans on the 7th, and fades to magnitude 9.5 by the 31st.

-- Brian Loader

7. 2015 RASNZ Conference

Dear Friends, Colleagues,

It is a pleasure to announce that the next conference of the Royal Astronomical Society of New Zealand (RASNZ) will be held at Lake Tekapo from 8th-10th May 2015. Our guest speakers will be Professors Gerry Gilmore (University of Cambridge) and Edward Guinan (Villanova University), and the Fellows Lecture for 2015 will be delivered by Associate Professor Karen Pollard from Canterbury University. Titles and abstracts for these talks will be released when they are available.

For further information on the RASNZ conference and registration please visit the conference website at www.rasnz.org.nz/Conference

The conference will be preceded by a two day symposium to celebrate the 50th anniversary of the Mount John University Observatory - see http://www.phys.canterbury.ac.nz/mtjohn50/ for registration information and other details of this meeting. Immediately after the conference the Ninth Trans-Tasman Symposium on Occultations (TTSO9) will also be held at the Godley Hotel, Lake Tekapo on 11th-12th May. For details see http://occultations.org.nz/meetings/TTSO9/TTSO9.htm. Note that registrations for TTSO9 can ONLY be made through the RASNZ Conference registration page.

The RASNZ standing conference committee invites and encourages anyone interested in New Zealand Astronomy to submit papers, with titles and abstracts due 1st April 2015. The link to the paper submission form can be found on the RASNZ conference website given above, or you can go to the RASNZ Conference Paper submission form. Please note that you MUST be registered for the conference to make a presentation. Even if you are just thinking of presenting a paper please submit the form, and we can follow up with you at a later date.

We look forward to receiving your submission and seeing you at conference.

Please feel free to forward this message to anyone who may find this of interest.

Sincerely yours, Warwick Kissling, RASNZ Standing Conference Committee

8. 9th Trans-Tasman Symposium on Occultations (TTSO9)

The RASNZ Occultation Section is pleased to announce that the 9th Trans-Tasman Symposium on Occultations (TTSO9) will be held at Lake Tekapo, New Zealand, over 11-12 May 2015. Comprehensive information about the meeting is available here:

http://occultations.org.nz/meetings/TTSO9/TTSO9.htm

The meeting will immediately follow the 2015 RASNZ Conference and the Mt John Observatory 50th Anniversary Symposium. Because attendance at all these meetings is expected to be high, accommodation space in Tekapo is likely to be limited. If you plan to attend any of these meetings we recommend that you book your accommodation early.

-- Murray Forbes.

9. 2017 Conference - Host Sought

The RASNZ Standing Conference Committee (SCC) invites interested societies, affiliated to the RASNZ, to offer to host the 2017 RASNZ conference. Conferences are usually held in May.

Information about hosting a conference, such as a guide to the facilities needed at the conference venue and an outline of the responsibilities of the Local Organising Committee which they will need to form, can be found here: RASNZ Conference Guidelines (please note you need to be a registered member on the web-site to access this link). In addition, please feel free to contact the SCC by email to This email address is being protected from spambots. You need JavaScript enabled to view it.. Please submit your offer to This email address is being protected from spambots. You need JavaScript enabled to view it. no later than 2015 April 17.

The SCC hopes to be able to make a recommendation for the host of the 2017 conference to the RASNZ Council at its meeting in May so that a formal invitation can be issued.

-- Glen Rowe, Chair, RASNZ Standing Conference Committee.

10. Eta Carinae's Stars Clash

Embedded in the lovely Carina Nebula, one of the great observing gems of the far-southern sky, Eta Carinae is the most massive, most luminous star within 10,000 light-years of us. (It's 7,500 light-years distant.) Astronomers now believe it's actually a binary star whose gigantic primary has roughly 90 times the Sun's mass and outshines it by 5 million times. Less is known about the secondary, but it too is thought to be enormous, with perhaps 30 solar masses and a million times the Sun's luminosity.

Eta Carinae erupted violently in 1843, ejecting perhaps 10 Sun's worth of mass - a truly titanic blast that would have destroyed a lesser star. This "erratic stellar monster," as one researcher dubbed it, briefly became the second-brightest star in the night sky. Today astronomers see the results of that outburst as an expanding two-lobed shell called the Homunculus Nebula.

More recently, space observatories found that Eta Carinae creates strong X-ray outbursts every 5.5 years. This happens whenever the paired stars are closest in their highly elongated orbit and separated by only about 225 million km - roughly Mars's distance from the Sun.

These periodic encounters are not just hi-and-bye affairs. It's more a clash of the titans. The larger star's extreme luminosity is driving dense stellar winds that carry off a Jupiter's worth of mass every year at roughly 400 km per second. The secondary also creates an intense outflow, one that's less dense yet has six times higher velocity.

Computer simulations by Thomas Madura (NASA Goddard Space Flight Center) and others suggest that the secondary's flow carves out a cavity in the primary's slower, denser wind - much as a moving boat creates a wake around it.

Nothing much happens when the two stars are widely separated. But when closest to each other, at periastron, the two flows collide violently, creating a shock boundary that heats the gas to tens of millions of degrees - hot enough to generate a torrent of X-rays that build gradually over many months and then drop off precipitously as the stars start to separate.

Madura and others at NASA's Goddard Space Flight Center have created a dramatic recreation of how the winds interact when they slam together that's worth watching. See it at the link below.

NASA's Swift spacecraft captured the most recent X-ray flare-up last July, and it was stronger than previous outbursts recorded in 1995, 2003, and 2009 by the Rossi X-ray Timing Explorer. Moreover, the tailing off of the emission spike was different too. One of the two stars' winds must have changed over time - but which?

Fortunately, observers could sort it out using a blue-light emission from ionized helium at 468.6 nanometres. As Mairan Teodoro (Western Michigan University) explains, the X-rays are produced on the side of the shock zone nearest the secondary. But the helium emission comes from the primary's dense slow wind - a crucial difference.

At the recent meeting of American Astronomical Society, Teodoro presented 22 years of spectroscopic observations of Eta Carinae gathered using a worldwide network of telescopes. (Amateurs played a crucial role in this campaign, by the way.) He says that the helium emission, first noted during 2003's periastron, has been steady to within about 20%. So the varying X-ray flux must be due to changes in the secondary star and its high-speed wind.

Frankly, astronomers know very little about the secondary - even its mass is something of a guesstimate. As Madura concedes, "We actually still don't know what the secondary star is, and that's one of the reasons why we're doing all this work." In fact, a big question mark remains about the 1843 eruption. "Everyone thinks it's the more massive star that threw off the mass [in 1843] to form the Homunculus Nebula," he says, "but to be honest we don't even know which star had the eruption."

-- Article by Kelly Beatty, copied from http://www.skyandtelescope.com/astronomy-news/eta-carinae-x-ray-pulse-01162015/?et_mid=717089&rid=246399573


Eta Carinae was monitored at Mt John Observatory as part of the international collaboration during May to October 2014. High resolution spectroscopic observations from the HERCULES spectrograph on the 1-metre McLellan telescope were obtained of this interesting unstable high-mass binary system in order to study the dynamics and activity system, including the interacting stellar winds. The binary system has an orbital period of 5.5 years. The components of this high mass binary system had their closest approach to each other in August 2014, during which time it was spectroscopically monitored from several observatories around the world. People involved in the UC/Mt John part of this project are Karen Pollard (UC/Mt John), Pam Kilmartin (UC/Mt John), Fraser Gunn (UC/Mt John), and Carolle Varughese (UC Dept Physics and Astronomy summer student).

-- From a note by Karen Pollard.

11. Inflation Signature Not Found in Plank Analysis

Confirming earlier suspicions, a joint analysis of data from the European Space Agency´s Planck satellite and the ground-based BICEP2 and Keck Array experiments has found no conclusive evidence of primordial gravitational waves. (See Newsletter No. 166, Item 8.)

The universe began about 13.8 billion years ago and evolved from an extremely hot, dense and uniform state to the rich and complex cosmos of galaxies, stars and planets we see today. An extraordinary source of information about the universe´s history is the cosmic microwave background, or CMB, the legacy of light emitted only 380,000 years after the Big Bang. ESA´s Planck satellite observed this background across the whole sky with unprecedented accuracy, and a broad variety of new findings about the early universe has already been revealed over the past two years.

But astronomers are still digging ever deeper in the hope of exploring even further back in time: they are searching for a particular signature of cosmic `inflation´ -- a very brief accelerated expansion that, according to current theory, the universe experienced when it was only the tiniest fraction of a second old. This signature would be recorded in gravitational waves, tiny perturbations in the fabric of space-time, that astronomers believe would have been generated during the inflationary phase.

Interestingly, these perturbations should leave an imprint on another feature of the cosmic background: its polarization. When light waves vibrate preferentially in a certain direction, we say the light is polarized. The CMB is polarized, exhibiting a complex arrangement across the sky. This arises from the combination of two basic patterns: circular and radial (known as E-modes), and curly (B-modes).

Different phenomena in the universe produce either E- or B-modes on different angular scales. Identifying the various contributions requires extremely precise measurements. It is the B-modes that could probe the universe´s early inflation. But this unique record of the very early universe is hidden in the polarization of the CMB, which itself only represents only a few percent of the total light.

Early 2014 the BICEP2 team presented results based on observations of the polarized CMB on a small patch of the sky performed in 2010-12 with their microwave telescope at the South Pole. The team also used preliminary data from another South Pole experiment, the Keck Array. They found curly B-modes in the polarization observed over stretches of the sky a few times larger than the size of the full Moon. The BICEP2 team presented evidence favouring the interpretation that this signal originated in primordial gravitational waves, sparking an enormous response in the academic community and general public.

However interstellar dust in our galaxy can produce a similar effect. The Milky Way is pervaded by a mixture of gas and dust shining at similar frequencies to those of the CMB. This foreground emission affects the observation of the most ancient cosmic light. Very careful analysis is needed to separate the foreground emission from the cosmic background. Critically, interstellar dust also emits polarized light, thus affecting the CMB polarization as well.

The BICEP2 team relied on models for galactic dust emission that were available at the time. These seemed to indicate that the region of the sky chosen for the observations had dust polarization much lower than the detected signal. The two ground-based experiments collected data at a single microwave frequency, making it difficult to separate the emissions coming from the Milky Way and the background.

The Plank satellite observed the sky in nine microwave and sub- millimetre frequency channels, seven of which were also equipped with polarization-sensitive detectors. By careful analysis, this multi- frequency data can be used to separate the various contributions.

The BICEP2 team had chosen a field where they believed dust emission would be low, and thus interpreted the signal as likely to be cosmological. However, as soon as Planck´s maps of the polarized emission from galactic dust were released, it was clear that this foreground contribution could be much higher than previously expected. In fact, in September 2014, Planck revealed for the first time that the polarized emission from dust is significant over the entire sky, and comparable to the signal detected by BICEP2 even in the cleanest regions.

So, the Planck and BICEP2 teams joined forces. They combined the satellite´s ability to deal with foregrounds, using observations at several frequencies, with the greater sensitivity of the ground-based experiments over limited areas of the sky, thanks to their more recent, improved technology. By then, the full Keck Array data from 2012 and 2013 had also become available. This joint work showed that the detection of primordial B-modes was not clear once the emission from galactic dust is removed.

Another source of B-mode polarization, dating back to the early universe, was detected in this study, but on much smaller scales on the sky. This signal, first discovered in 2013, is not a direct probe of the inflationary phase but is induced by the cosmic web of massive structures that populate the universe and change the path of the CMB photons on their way to us. This effect is called `gravitational lensing,´ since it is caused by massive objects bending the surrounding space and thus deflecting the trajectory of light much like a magnifying glass does. The detection of this signal using Planck, BICEP2 and the Keck Array together is the strongest yet.

As for signs of the inflationary period, the question remains open. The joint study sets an upper limit on the strength of gravitational waves from inflation. They might have been generated at the time but at a level too low to be confirmed by the present analysis. The analysis shows that the amount of gravitational waves can probably be no more than about half the observed signal. The gravitational wave signal could still be there, and the search is definitely on.

For the full text and images see http://sci.esa.int/planck/55362-planck-gravitational-waves-remain-elusive/

-- From a European Space Agency press release forwarded by Karen Pollard.

12. How to Join RASNZ

RASNZ membership is open to all individuals with an interest in astronomy in New Zealand. Information about the society and its objects can be found at http://rasnz.org.nz/RASNZInfo/MemberBenefits.shtml A membership form can be either obtained from This email address is being protected from spambots. You need JavaScript enabled to view it. or by completing the online application form found at http://rasnz.org.nz/RASNZInfo/Membership/ Basic membership for the 2015 year starts at $40 for an ordinary member, which includes an electronic subscription to our journal 'Southern Stars'.

13. Gifford-Eiby Lecture Fund

The RASNZ administers the Gifford-Eiby Memorial Lectureship Fund to assist Affiliated Societies with travel costs of getting a lecturer or instructor to their meetings. Details are in RASNZ By-Laws Section H.

14. Quote

 

"'For the first time in New Zealand, and possibly for the first time in the world, the prediction of the occurrence of an aurora was made with certainty on August 22,1939.... The director of [Carter Observatory], Mr M. Geddes, noticed in the case of a number of aurorae that earth currents which accompanied the displays and seriously interfered with telephonic communications frequently began in the afternoon preceding the auroral display. Arrangements were consequently made with the post office for prompt advice of such interference, and when earth currents became evident on the afternoon of August 22nd last it was possible to warn the photographic stations... of the brilliant aurora which became visible as darkness fell.' R.A. McIntosh made no mention of solar activity, long suspected but not yet shown to play a role in the aurora. That connection was finally established in 1948."

-- Quoted from The Sky, March 1940, in Sky and Telescope, March 2015, p.10.


Newsletter editor:

Alan Gilmore   Phone: 03 680 6817
P.O. Box 57   Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Lake Tekapo 7945
New Zealand