Microlensing parallax

I am doing a little work in microlensing parallax between two observatories. First step: replicate others’ work! Here is my attempt to replicate Figure 1 of Henderson & Shvartzvald (2016).

And here is Figure 2:

Figure 3:

Here is a scatter plot of mu_rel for $D_l = 1$kpc and $D_s = 8.2$ kpc, with the bulge velocity distribution used for the lens:

Animation of the positions of Earth and Kepler, in 2022, projected onto the observer plane, pointing towards a source at the centre of the K2 superstamp:

Plot of theta for Kepler-Earth, over a year:

Using the same assumptions as H&S, here is their Figure 3 replicated:

Here is some work going beyond H&S Figure 3, using the samples from the actual observer ephemerides along with the Galactic model draws:

Here is Figure 4 replicated:

NJR Honours Projects for 2018

Here’s my list of Honours projects for 2018. If you are keen to do one of these, please email me or drop by to discuss.

1. University of Auckland Ground Station 1

The University’s first CubeSat mission is scheduled to fly late 2018. We have a ground station on top of the Physics building to communicate with satellites. This station requires final calibration and testing, and development of corresponding control and analysis software. This work will be done in conjunction with the Auckland Programme for Space Systems, using the new APSS laboratories on Symonds Street and the Department of Physics Electronics Laboratory. You will be working with students and staff in the Faculty of Engineering, as well as in the Faculty of Science. You will also assist in the preparation to communicate with the first APSS satellite mission via the Defence Technology Agency’s ground station, working with DTA staff to ensure a smooth connection between the DTA systems and the University network.

This will be of interest to you if:

  • you have a reasonable grasp of radio communications,
  • good electronics / lab skills,
  • good computer network skills,
  • excellent written and oral communication skills,
  • an interest in space system hardware.
Listen and track satellites and help us get ready for launch in 2018!

Listen and track satellites and help us get ready for launch in 2018!

 

2. Hauraki Gulf Space Observation Honours Projects

Coastal science is both complex and complicated. There is a lack of detailed information on the interaction between ocean and coast, the coastal ecology and the relationships between the coastal environment and life on and near the coast. Each of the following projects relates to an overall goal of imaging the Hauraki Gulf from space. These earth observation projects are multi-disciplinary and will be carried out in conjunction with the Department of Marine Science and the Department of Engineering Science in the Faculty of Engineering.

2a. Geosynchronous CubeSat Feasibility Study

For this project you will scope and design a small satellite system that is capable of imaging the Hauraki Gulf to a few metres resolution from a geosynchronous orbit. These image data will be used to measure coastal sea colour, elevation, turbidity and reflectance. You will need to investigate commercial off the shelf optics and imaging systems that can provide the necessary resolution, and can operate within the power, volume, mass and communication bandwidth budgets of a small satellite system bus. You will need a good grounding in optics, electronics and some signal processing. Experience in space systems is not required. You must have excellent written and oral communication skills as you will be required to interact with a range of individuals both across different University Faculties and Departments, as well as external hardware and service providers.

This will be of interest to you if:

  • you have an interest in space system mission design,
  • good electronics / optics skills,
  • familiarity with signal processing and data analysis,
  • excellent written and oral communication skills.

2b. Earth Observation Satellite Data Analysis

This project will require you to make a census of the available satellite imaging and radar data of the Hauraki Gulf. A number of existing satellite missions make their data freely available, such as ESA’s Sentinel optical and synthetic aperture radar satellites. You will investigate what sources of data are available, summarise basic meta data of each data source (e.g. how often images are taken, wavelengths, resolutions, etc). You will work with satellite imaging experts both in Auckland and at the Centre for Space Science Technology to identify modes of imaging that will provide the information required to address the science goals of the project — or identify a need for more imaging. You will also use existing analysis software to do preliminary data analysis for suitable datasets.

This will be of interest to you if:

  • you have an interest space-based data analysis,
  • very good programming skills,
  • familiarity with image analysis,
  • excellent written and oral communication skills.

 

3. Design a UV space telescope mission to detect intermediate mass black holes

Intermediate mass black holes are theorised to exist in our Galaxy. They are difficult to detect, however. One channel for discovery is by looking for tidal disruption flares (TDFs), wherein a companion to a black hole is disrupted the the gravitational distortion of the BH and emits bursts of radiation. These transient events are highly energetic, but emit most of the radiation in the UV, making ground-based observations only sensitive to the brightest events. This project will be to design a small satellite to make UV observations from space, in order to detect fainter TDFs. You will be working with colleagues at The University of Warsaw.

This will be of interest to you if:

  • you have an interest in space system mission design,
  • you have a good background in — or at least a strong interest in — astronomy or astrophysics,
  • good electronics / optics skills,
  • excellent written and oral communication skills.

 

4. Astronomical Seeing Measurements in the Greater Auckland Area.

One of the Department’s 40 cm Meade telescopes has been converted into a seeing monitor. Seeing is a measure of atmospheric turbulence. This project will involve the student making seeing observations at various sites in the Greater Auckland area, analysing the results and publishing these. The student will have to be comfortable working at night, and have a full driver’s licence. You will make seeing measurements using the dedicated software written for the instrument, as well as a commercial seeing analysis package and compare the results.

Use one of these!

 

This will be of interest to you if:

  • you have an interest in astronomy,
  • very good programming skills,
  • familiarity with image analysis,
  • excellent written and oral communication skills.

 

5. Multidimensional Dataset Visualisation with an Oculus Rift

This project will require the student to investigate multidimensional astronomical datasets using an Oculus Rift. Students should have a high level of programming ability. You will be using the iViz visualisation software from Virtualitics (no experience necessary).

This will be of interest to you if:

  • you have an interest in data analysis, and human-computer interaction,
  • excellent programming skills,
  • excellent written and oral communication skills.

Oculus Rift DK2

 

NJR Honours Projects for 2017

Here’s my list of Honours projects for 2017. If you are keen to do one of these, please email me or drop by to discuss.

1. Construct a Satellite Ground Station

In 2018, the University will start to launch CubeSats into low earth orbit. We will need a ground station to communicate with our satellites. The project will require the student to construct an antenna system comprising a software defined radio, corresponding control and analysis software, and display the information in a suitable format. This work will be done in conjunction with the Auckland Programme for Space Systems, using the new APSS laboratories on Symonds Street and the Department of Physics Electronics Laboratory.

Listen and track satellites and help us get ready for launch in 2018!

Listen and track satellites and help us get ready for launch in 2018!

2. Get into Machine Learning and classify Supernovae (in conjunction with JJ Eldridge)

This project will involve training a machine learning algorithm to classify standard supernovae lightcurves. The work will then be to see how the classifier copes with rarer, non-standard supernovae light curves, adapting the learning algorithm to correctly classify these non-standard curves as well. This work could then be extended to be part of the Transient and Variable Survey work of the Large Synoptic Survey Telescope (LSST), making predictions on how well the LSST will discover these rarer supernovae light curves.

Classify rare and exotic supernovae using machine learning!

Classify rare and exotic supernovae using machine learning!

 

3. Astronomical Seeing Measurements in the Greater Auckland Area.

One of the Department’s 40 cm Meade telescopes has been converted into a seeing monitor. Seeing is a measure of atmospheric turbulence. This project will involve the student making seeing observations at various sites in the Greater Auckland area, analysing the results and publishing these. The student will have to be comfortable working at night, and have a full driver’s licence.

Use one of these!

 

 

4. Multidimensional Dataset Visualisation with an Oculus Rift

This project will require the student to investigate the software available for displaying multidimensional datasets using an Oculus Rift. The key objectives are to have a suite of software tools available to allow a user to navigate complex multidimensional data via virtual reality immersion. Students should have a high level of programming ability.

Oculus Rift DK2

 

5. Detecting Atmospheric Meteor trails

Meteors entering the Earth’s atmosphere leave a trail of ionised particles. We have a software-defined radio system set up to detect radio signals from Christchurch which are forward-scattered off these trails. This system is working successfully, but can be improved upon. The honours project will comprise optimising the system to improve the number of detected meteor trails, to compile statistics of this year’s meteor showers and report them to the International Meteor Organisation. The project would also comprise making the observed data available via the Internet in real-time.

Analyse these!

6. Design a CubeSat to perform Synthetic Aperture Radar measurements

With the Auckland Programme for Space Systems starting here at the University of Auckland, we are beginning to think about how New Zealand can benefit from utilising space. This project will be to design a synthetic aperture radar system that can be carried on a CubeSat (a 10x10x10 cm) satellite. Careful attention will need to be paid to power budgets, communication bandwidth budget and of course mass and volume budgets. Some experience in electronics would be an advantage.

Design a CubeSat!

Microlensing Study Suggests Most Common Outer Planets Likely Neptune-mass

SCCZEN_A_280606splOBSERV2_620x310

Gravitational microlensing is a method for discovering extra-solar planets. It is different to other techniques in that it is sensitive to planets in orbits around their host star where scientists think planets form most readily. In a recent work, Daisuke Suzuki of the Japan/New Zealand MOA collaboration announced that the most likely mass of such planets is about that of Neptune. The story was picked up by the New Zealand Herald today.

This graph plots 4,769 exoplanets and planet candidates according to their masses and relative distances from the snow line, the point where water and other materials freeze solid (vertical cyan line). Gravitational microlensing is particularly sensitive to planets in this region. Planets are shaded according to the discovery technique listed at right. Masses for unconfirmed planetary candidates from NASA's Kepler mission are calculated based on their sizes. For comparison, the graph also includes the planets of our solar system. Credit: NASA's Goddard Space Flight Center

This graph plots 4,769 exoplanets and planet candidates according to their masses and relative distances from the snow line, the point where water and other materials freeze solid (vertical cyan line). Gravitational microlensing is particularly sensitive to planets in this region. Planets are shaded according to the discovery technique listed at right. Masses for unconfirmed planetary candidates from NASA’s Kepler mission are calculated based on their sizes. For comparison, the graph also includes the planets of our solar system.
Credit: NASA’s Goddard Space Flight Center

To reach this conclusion, Suzuki and his co-authors analysed a set of microlensing planets that have already been discovered, conducting a statistical analysis to infer the most likely planet mass of these cold planets. One of the planets included in the planet which I announced in Monthly Notices last year. The discovery and announcement of these planets power the sort of statistical analyses like that of the Suzuki et al result.

Neptune-mass exoplanets like the one shown in this artist's rendering may be the most common in the icy regions of planetary systems. Beyond a certain distance from a young star, water and other substances remain frozen, leading to an abundant population of icy objects that can collide and form the cores of new planets. In the foreground, an icy body left over from this period drifts past the planet. Credit: NASA's Goddard Space Flight Center/Francis Reddy

Neptune-mass exoplanets like the one shown in this artist’s rendering may be the most common in the icy regions of planetary systems. Beyond a certain distance from a young star, water and other substances remain frozen, leading to an abundant population of icy objects that can collide and form the cores of new planets. In the foreground, an icy body left over from this period drifts past the planet.
Credit: NASA’s Goddard Space Flight Center/Francis Reddy

Story: https://www.nasa.gov/feature/goddard/2016/most-common-outer-planets-likely-neptune-mass

Paper: http://iopscience.iop.org/article/10.3847/1538-4357/833/2/145

arXiv version of paper: http://adsabs.harvard.edu/abs/2016arXiv161203939S

Additional graphics: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=12425

Video on YouTube: https://youtu.be/qzlR3kBCLYM

Wide-orbit planet discovered around binary star with MOA-II and HST

From the press release from the Space Science Telescope Institute:

Astronomers using NASA’s Hubble Space Telescope, and a trick of nature, have confirmed the existence of a planet orbiting two stars in the system OGLE-2007-BLG-349, located 8,000 light-years away towards the center of our galaxy.

The planet orbits roughly 300 million miles from the stellar duo, about the distance from the asteroid belt to our sun. It completes an orbit around both stars roughly every seven years. The two red dwarf stars are a mere 7 million miles apart, or 14 times the diameter of the moon’s orbit around Earth.

The Hubble observations represent the first time such a three-body system has been confirmed using the gravitational microlensing technique. Gravitational microlensing occurs when the gravity of a foreground star bends and amplifies the light of a background star that momentarily aligns with it. The particular character of the light magnification can reveal clues to the nature of the foreground star and any associated planets.

The three objects were discovered in 2007 by an international collaboration of five different groups: Microlensing Observations in Astrophysics (MOA), the Optical Gravitational Lensing Experiment (OGLE), the Microlensing Follow-up Network (MicroFUN), the Probing Lensing Anomalies Network (PLANET), and the Robonet Collaboration. These ground-based observations uncovered a star and a planet, but a detailed analysis also revealed a third body that astronomers could not definitively identify.


Source: Hubblesite.org

Check out the video describing gravitational microlensing and the discovery!

Doubly eclipsing binaries

It is nothing special, but I have discovered several doubly eclipsing binaries in MOA database. The figure below is one of them. It was achieved by first substracting the mean light curve with 200 bins from the one folded with P=0.409d and then redoing the period analysis to see if there is any hidden periodic variation.

mao-61499-gb10-R-3

Funded MSc Thesis — 2017 — Virtual Reality Data Visualisation

I have funding available (one year, domestic) for an MSc student to develop our capacity to visualise multi-parameter datasets using virtual reality. The full advertisement is below. If you are interested, please get in touch.

Oculus Rift DK2 Oculus Rift DK2

The Department of Physics, in collaboration with the Intelligent Vision Systems Team in the Department of Computer Science, has funding available for an MSc thesis student to develop tools for the visualisation of multi-parameter data sets using virtual reality. The student will continue to develop existing prototype code to improve our capability to interrogate data sets using an Oculus Rift. Data from the fields of astronomy, cosmology and drone flights are available to test and improve the codes used. The student will also investigate the use of hand gesture control as part of an improved human control interface with the analysis codes. Some programming experience is required. The funding for this project comprises one year’s MSc (domestic) fees.

Plot.ly

I’ve become a fan of Plot.ly — an online service for plotting data and sharing it. I was mainly interested in figuring out how to plot my useage of the NeSI PAN cluster computer — particularly for seeing how many computer nodes I was using at any given time, and how many jobs were left to do. I found that with Plot.ly you can stream data to their server and it will update a plot as the new data come in. Their tutorials for setting this up are reasonably straightforward, and I managed to write a little python code to stream the state of my jobs on the cluster (with a little help of crontab and scp):

Link to live streaming plot.

Screenshot from this afternoon:

plotly

2016 Honours Projects with NJR

Here’s my list of Honours projects for 2016. If you are keen to do one of these, please email me or drop by to discuss.

1. Creating a Differential Image Motion Monitor for Astronomical Seeing

This project will require the student to set up one of the Department’s 40 cm Meade telescopes as a seeing monitor. Seeing is a measure of atmospheric turbulence. This project will require the student to work with the engineering facilities to affix a DIMM mask to the telescope, set up a CCD camera on the telescope and run DIMM observation software to measure atmospheric seeing. The student will have to be comfortable working at night, and have a full driver’s licence.

Use one of these!

         Use one of these!

 

 

 

2. Multidimensional Dataset Visualisation with an Oculus Rift

This project will require the student to investigate the software available for displaying multidimensional datasets using an Oculus Rift. The key objectives are to have a suite of software tools available to allow a user to navigate complex multidimensional data via virtual reality immersion. Students should have a reasonable level of programming ability.

Use one of these!

             Use one of these!

 

 

3. Finding Earth-sized planets orbiting White Dwarf stars

This project will require the student to obtain estimates of the number of white dwarf stars visible in the 1.8 meter MOA-II telescope field of view, estimate how many of these systems would have a transiting earth-sized planet, and propose an observation schedule for use by MOA to discover these planets.

Find some of these!

                   Find these!

 

 

 

4. Detecting Atmospheric Meteor trails

Meteors entering the Earth’s atmosphere leave a trail of ionised particles. We have a software-defined radio system set up to detect radio signals from Christchurch which are forward-scattered off these trails. This system is working successfully, but can be improved upon. The honours project will comprise optimising the system to improve the number of detected meteor trails, to compile statistics of this year’s meteor showers and report them to the International Meteor Organisation. The project would also comprise making the observed data available via the Internet in real-time.

Analyse these!

                                                 Analyse these!

                                                 Analyse these!

Equipment issues

There were some equipment issues on the 27th and 28th of September, as well as the 9th and 11th of October so these days do not contain the full 24 hours worth of data, as the software was not recording continuously on these days.  The software, SDR# has a tendency to crash from time to time, usually after connecting to the computer to check that the noise floor has not dropped or increased. On 27th of September, I checked the program once just before noon and it was only the next day in the morning that I noticed that there were no files downloading in the DropBox throughout the day and over night. After connecting to the computer to see if it was still working, I saw that the program was not responding and I had to restart it. Since it seems that it was not be responding for most of the day of the 27th and over night on the 28th of September, no signals were detected and recorded and therefore those two days are also missing some data. The same thing again happened on the 9th of October, but I checked the program at around 10pm so only the data during the day from about noon until 10pm is missing. Seeing as those are approximately the times when there are the least amount of meteors entering our atmosphere, I can assume that majority of the signals for the 9th of October were recorded and only a few were missed.

A few days before the 11th of October, the noise floor started varying a lot and many false positive files were recorded that filled up the DropBox to its capacity. On the 11th of October, overnight, the noise floor dropped by a further 2dB and no files were recorded – both signals and random, varying peaks were missed. I made a decision to drive out to Ardmore with a USB stick to manually transfer the data from the computer to my laptop, which I used for analysing the data, and also check the equipment to see why the noise floor was varying so much. I checked all of the connections to see if anything had come loose and thus became a source of extra noise, including the connections inside of the balun of the antenna. After I checked the balun, the random peaks disappeared and the significant varying of the noise floor stopped and there was also an increase in signal detection. This could indicate that the connections inside the balun had either come loose throughout the project, maybe due to storms and wind at the location, or they were never properly screwed in from the beginning. I got in touch with a technician about the loose connection and this is currently in the process of being fixed. The increase in signal detection could also be due to the increased meteor activity from the Orionids meteor shower.

Since the onset of the project, a new version of the receiver has been released, called Airspy R2 so in the future, it might be useful to look into investing into the new receiver to see if it would increase the sensitivity of the equipment and be able to detect even more faint signals. A signal amplifier could be added to the antenna to amplify any low power signals, allowing for them to also be recorded. However, an amplifier could amplify the noise as well, thus looking into shielding the receiver would be necessary if an amplifier was to be added. A filter could also be added if wished, but it is not necessary as there is a frequency setting in the software that allows only the target frequency to trigger recording.

It has been very exciting and interesting to work on this project this year and I hope that next year someone will take over and carry on improving my set up and observing and recording meteor activity here in New Zealand.