2018 March 29:     Liz defends her PhD thesis on dead monsters at cosmic high noon

Liz, seen in the centre of the photo that also shows her thesis defence committee (Rob Thacker, Laura Parker, Ivana Damjanov, and Marcin Sawicki), has successfully defended her PhD thesis entitled “Massive Passive Galaxies at z~1.6”.  Well done, Dr. Liz!

Liz’s thesis concerns UMPGs - Ultra Massive Passive Galaxies that by redshift ~1.6 have already ceased star formation but not before converting close to a trillion (1011.5) solar masses of gas into stars. These “dead monsters” which are associated with extremely massive and rare dark matter halos (1014 solar masses of dark matter!), reside on the very massive end of the galaxy stellar mass function at these redshifts.  Their clustering and high stellar masses suggest that they may be the progenitors of some of today’s central galaxies of massive galaxy clusters such as Coma and Virgo.  Despite clearly being associated with massive dark matter halos, they have very few massive companions so any future growth of their mass may only be due to the accretion of low-mass satellites.

2018 August 21:     Nathalie defends her MSc thesis on galaxy mergers

Nathalie successfully defends her thesis on the evolution of the galaxy-galaxy merger rate using data from the CLAUDS+HSC surveys.  Nathalie has implemented a machine-learning, automated way to identify merging galaxies in the images from our very deep and very wide dataset. This approach, which uses random forests (ensembles of decision trees) is able to process large amounts of data much more quickly than a human could, while also producing results that are reproducible (a key consideration in any scientific measurement!).  Using this method, Nathalie has found that the merger rate was higher in the past, increasing with redshift as (1+z)2.5, as shown in the figure.

2018 September 1:     Angelo joins the team

Angelo George arrives at Saint Mary’s for his MSc studies.  He will be working both with me and with Ivana Damjanov. Welcome to SMU, Angelo!

2018 April 10:     Ikuru Iwata arrives for a sabbatical stay

Ikuru Iwata, now on leave from his post as Associate Director of the Subaru Telescope, has just arrived in Halifax for a sabbatical visit.  Ikuru works in the field of galaxy formation and evolution and is an expert in studying how ionizing photons escape from distant galaxies.  These photons are though to be responsible for “reionizing the Universe”, which is a transition that happend at high redshift when intergalactic gas changed from neutral hydrogen to plasma.  I look forward to many good interactions with Ikuru and to working with him on constraining the escape rates of ionizing photons from galaxies and quasars in the CLAUDS+HSC data.

2018 May 1:     Martin and Harrison join the team

Martin Hellmich and Harrison Souchereau join the SMU galaxy evolution group as summer students.  Martin will be working with me to produce realistic simulations of galaxies that will be observed with the planned CASTOR ultraviolet imaging space telescope.  Harrison will be working with Ivana and me on measuring the shapes of galaxies in deep images from the Subaru telescope.  Welcome to the team, guys!

2018 September 3-7:     Dead monsters at cosmic noon visit Sicily

I attend the conference on massive galaxies (properly called “The Birth, Life and Fate of Massive Galaxies and Their Central Beating Heart”) on Favignana Island off the coast of Sicily.  Most consider “massive galaxies” to be objects with stellar masses of ~1010.5-11 solar masses, but I present our results on truly ultra-massive galaxies, those with masses greater than 1011.5 solar masses, focusing on particular on those that have already stopped forming stars at redshift z~2 (“dead monsters at cosmic high noon”). I presented results from both Liz’s and Gurpreet’s theses; you can see my presentation slides by clicking here.

2018 June 5:     Thinbaud’s environments paper accepted by MNRAS!

Thibaud’s paper on the quenching of low-mass galaxies is accepted for publications in Monthly Notices of the Royal Astronomical Society.  One key conclusion is that low-mass fast-quenched galaxies, the galaxies that are responsible for the 2nd Schechter component in the galaxy mass function, reside in dense environments. There is a lot more in the paper than that, so have a look at the paper which you can do by clicking here.

2018 January 19:     Paper on the missing mass problem accepted by MNRAS!

Bobby’s paper that studies the spatially-resolved spectral energy distributions of high-z galaxies is accepted for publications in Monthly Notices of the Royal Astronomical Society.  The key conclusion of the paper is that stellar masses of distant galaxies are by factors of 2 or more underestimated by standard SED-fitting techniques.  One consequence of this is that, once corrected for the bias, the universe has more stellar mass assembled at high redshift than people previously thought; this solves the “missing mass problem”, the discrepancy between the observed stellar mass density and the integral of the star formation rate density --- a discrepancy that has bothered the community for the past decade or more. You can have a look at Bobby’s paper by clicking here.

2018 September 3-7:     New MCAO capability for Gemini and GIRMOS

The NSF just announced that it will fund the construction of a new state-of-the art multi-conjugate adaptive optics (MCAO) facility for Gemini-North. This will provide images that will be sharper than those from Hubble and these will feed our GIRMOS instrument whose design and construction is just getting underway!  An exciting and unprecedented scientific capability coming to Mauna Kea and world-wide astronomy.  Click here for more details. 

2018 October 10-12:     CLAUDS at Permimeter

I give a talk on the CLAUDS+HSC-SSP collaboration at the Subaru session of the Canadian Wide-Field Astronomy Workshop at Perimeter Institute in Waterloo.  The workshop explored many very interesting ideas for the future of Canadian wide-field astronomy, including projects dear to my heart (and with significant involvement by me or my group):  CASTOR, MSE, Subaru.

2018 December 4-5:     GIRMOS project officially starts!

The GIRMOS project had its kick-off meeting in Toronto on Dec 4-5.   Over the next 5 years we will design and build the next-generation AO-fed multi-object integral-field spectrograph for Gemini. In addition to being a state-of-the-art instrument with which we plan to do massive surveys of galactic structure and kinematics out to z~3, GIRMOS is also a prototype for a future TMT instrument.   I am super-excited about all this, and about the fact that at SMU we will be building the data processing pipeline for this state-of-the-art new instrument.

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