All-Sky Automated Survey for Supernovae
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NEWS: Our first supernova discovered with "Cassius"! (June 2014)
We are taking data with our two CTIO-based "Cassius" telescopes! (May 2014)
We are taking and reducing in real time data with four telescopes in Hawaii (Dec. 2013).

ASAS-SN Transients | APOW: Picture of the Week | Channel | Twitter | ASAS (Warsaw)

What is ASAS-SN?

The sky is big: even in the present day, only human eyes fully survey the sky for the transient, variable and violent events that are crucial probes of the nature and physics of our Universe. We plan to change that with our "All-Sky Automated Survey for Supernovae" (ASAS-SN or "Assassin") project, which will (eventually) automatically survey the entire visible sky every night down to about 17th magnitude, more than 10,000 times deeper than human eye. Such a project is guaranteed to result in many important discoveries, some of them potentially transformative to the field of astrophysics.

ASAS-SN is currently comprised of two units. ASAS-SN Unit-1, known as "Brutus", which also happens to be the name of the Ohio State mascot, is comprised of four robotic 14-cm telescopes deployed at the Haleakala station of the Las Cumbres Observatory Global Telescope Network. ASAS-SN Unit-2, named "Cassius", consists of two 14-cm telescopes deployed at the LCOGT Cerro Tololo station. Together, these allow us to observe a total of approximately 15,000 square degrees each clear night. Eventually we would like to deploy a total of 16 telescopes at four different sites, allowing us to survey the entire visible sky every night. We started real-time reduction and analysis of "Brutus" four-telescope data in December 2013 and are continuing to make interesting discoveries. In addition, the "Cassius" two-telescope system is now making discoveries as well.

We are discovering numerous supernovae in both hemispheres (38 so far, 9 in June and 11 in May 2014).

We continue to discover numerous bright cataclysmic variables, many of which are being intensely observed by professional and amateur astronomers.

Here are some of our most exciting objects:

ASASSN-14dz (July 2014). SN Type Ia in Mrk 842. V=15.7, about 95.3 Mpc away. Our 40th supernova!

ASASSN-14dl (Cassius discovery, June 2014). SN Type II in 6dF J1221502-241004. V=16.6, about 62.6 Mpc away.

ASASSN-14dd (Cassius discovery, June 2014). SN Type Ibn in NGC 2466. V=15.6, about 75 Mpc away.

ASASSN-14dc (June 2014). SN in 2MASX J02183825+3336556. V=15.8, our furthest away and most luminous supernova so far (about 200 Mpc away, M_V=-20.6).

ASASSN-14db (Cassius discovery, June 2014). Luminous SN Type I in ESO 075-G049. V=16.3, about 158 Mpc away.

ASASSN-14cu (Cassius discovery, June 2014). SN Type Ia in 2MASX_J12470274-2414435. V=16.2, about 108 Mpc away. The first supernova discovered with our Cassius unit!

ASASSN-14co (June 2014). SN Type Ia in PGC 056486. V=16.9, about 142 Mpc away. Our 30th supernova!

ASASSN-14cl (June 2014). A very large amplitude CV outburst that has been observed almost 20,000 times!

ASASSN-14be (May 2014). Extreme (delta V>6.6 mag) M-dwarf flare.

ASASSN-14az (May 2014). Bright SN Type IIb in GALEXASC J234448.27-020653.4. V=14.5; our closest supernova so far at about 23 Mpc away.

ASASSN-14ax (May 2014). SN Type Ia in SDSS J171000.70+270619.6. V=16.5, about 140 Mpc away. Our 20th supernova!

ASASSN-14as (May 2014). SN Type Ia in MGC+06-29-001. V=16.9; our furthest SN at the time of discovery, about 160 Mpc away.

ASASSN-14ae (January 2014). A Tidal Disruption Event (TDE) in SDSS J110840.11+340552.2 (z=0.04367). Discovered right near our limit of V=17.0, about 200 Mpc away, this is the closest TDE candidate ever discovered in optical wavelengths.

ASASSN-13dn (December 2013). SN Type II in SDSS J125258.03+322444.3. V=15.7, about 100 Mpc away. This was only our second non-Type Ia supernova, out of 15 discovered at that point, and at absolute V magnitude of approx. -19.3 it is very luminous.

ASASSN-13dm (December 2013). SN Type Ia in PGC 2816341. V=15.9, about 70 Mpc away. The first ASAS-SN supernova found using four-telescope configuration.

We started real-time reduction and analysis of "Brutus" two-telescope data in April 2013 and we had a number of exciting discoveries:

ASASSN-13dl (October 2013). SN Type Ia in Uncatalogued Galaxy. V=16.8, about 120 Mpc away.

ASASSN-13dd (September 2013). SN Type Ia. V=15.2, about 50 Mpc away.

ASASSN-13cp (August 2013). SN Type Ia. Our 10th supernova!

ASASSN-13co (August 2013). SN Type IIP. Our first non-Ia supernova, about 90 Mpc away!

ASASSN-13ck (August 2013). Large amplitude outburst (8 magnitudes) cataclysmic variable.

ASASSN-13cc (August 2013). SN Type Ia, 40 Mpc away in NGC 1954.

ASASSN-13cb (August 2013). Extreme (delta V~9 mag) M-dwarf Flare.

ASASSN-13bb (July 2013). SN Type Ia, our 2013 July 4th supernova.

ASASSN-13av (June 2013). SN Type Ia. Our third supernova!

ASASSN-13ar (June 2013). SN Type Ia. Our second supernova!

ASASSN-13an (June 2013). SN Type Ia. Our second supernova!

AGN Outburst and Dramatic Seyfert Type Change in NGC 2617 (April/May 2013). See also ATel #5103, #5059 and #5039.

We have also discovered a number of bright Cataclysmic Variables, see ATel #4987, #4999, #5052, #5082, #5102, #5118, #5168, #5186, #5195.

Generally we are posting our real-time discoveries using ATel, so if you interested in being notified of our results, you should subscribe to that useful service, and also see our ASAS-SN Transients page.

We are not yet fully "All-Sky", but we are getting there, see below where our supernova discoveries announced so far are located on the sky:

At this point we are focused on discovering nearby supernovae, but we like all kinds of variable objects, so if there is an object with V-band magnitude between V~10 and V~17 that we might have in our data, send us an e-mail and we will check what we have. This procedure will be more automated in the near future, stay tuned!

ASAS-SN Team:

At OSU: Bianca Davis, Tom Holoien, Chris Kochanek, Ben Shappee, Kris Stanek, Jacob Jencson, Udit Basu (high school student), John Beacom;

José Luis Prieto (Universidad Diego Portales);

At Warsaw University Observatory: Grzegorz Pojmanski, Dorota Szczygiel;

Joseph Brimacombe (Coral Towers Observatory);

David Bersier (LJMU).

We thank LCOGT and its staff for their continued support of ASAS-SN, especially M. Dubberley, M. Elphick, S. Foale, E. Hawkins, D. Mullens, A. Pickles, W. Rosing, R. Ross and Z. Walker.

A crucial part of our project is the follow-up effort with bigger telescopes to get confirmation imaging (Brutus has 7.5" pixels) and spectroscopy. Sometimes a space-based telescope is needed: outburst of the AGN in NGC 2617 has been monitored by Swift. A number of people have kindly contributed their own telescope time to help us in our effort, which we most appreciate! Here are the names of our collaborators on ASAS-SN results annouced so far: S. Adams (Ohio State), A. Campillay (Las Campanas Observatory), C. Choi (Seoul National University), C. Contreras (Las Campanas Observatory), C. Copperwheat (LJMU), G. De Rosa (Ohio State), M. Dietrich (Ohio University), M. Fausnaugh (Ohio State), D. Grupe (Penn State), D. Gifford (University of Michigan), M. Giustini (XMM-Newton Science Operation Centre), C. Gonzalez (Las Campanas Observatory), A. Goulding (CfA), K. Hainline (Dartmouth), D. Hartmann (Clemson), R. Hickox (Dartmouth), R. Hounsell (STScI), D. Howell (LCOGT), E. Hsiao (Las Campanas Observatory), M. Im (Seoul National University), A. Kaur (Clemson), S. Komossa (Max-Planck Institut fur Radioastronomie), M. Koss (IfA), P. Lira (U. Chile), K. Leighly (University of Oklahoma), S. Mathur (Ohio Sate), N. Morrell (LCO), A. Mosquera (Ohio State), D. Mudd (Ohio State), J. Nugent (University of Oklahoma), B. Peterson (Ohio State), M. Phillips (Carnegie Observatories), R. Pogge (Ohio State), A. Porter (Clemson), J. Rich (Carnegie Observatories), D. Sand (Texas Tech University), S. Schmidt (Ohio State), A. Sheffield (Columbia), S. Starrfield (ASU), M. Wagner (LBTO), A. Wilber (ASU), C. Woodward (U. Minnesota), S. Valenti (LCOGT), S. Villanueva (Ohio State), Y. Yoon (Seoul National University), Y. Zu (Carnegie Mellon).

So when you get an e-mail or a phone-call from us, asking to collaborate on a new exciting ASAS-SN target, we hope you will say "yes"!



ASAS-SN Hardware:

Our team makes ASAS-SN a success, but we also need excellent hardware to aid us in our ultimate goal of studying real-time variability of the entire sky:

To achieve large field of view with a very stable and uniform point-spread-function (PSF) across the field, we use Nikon AF-S NIKKOR 400mm f/2.8G ED VR AF lenses. We had high expectations for these lenses and were not disappointed: we obtain very stable and sharp images for many nights in a row. This is crucial for the image subtraction method, which we employ to detect transients, to work best.

Since we are using relatively small telescopes (lenses), we cannnot afford to waste many photons. As our detectors we have selected ProLine PL230 CCD cameras from FLI, with back-iluminated E2V sensors, giving us high QE, low-noise and fast readout (and of course they are electrically cooled). To cover several thousand square degrees each night, we take many hundreds of images nightly, and we have been very happy with the reliability of our cameras.


This material is based upon work supported by the National Science Foundation under Grant number AST-0909916 (2009-2013).

If you think monitoring the Variable Universe is a good idea and you would like to donate to that cause, please contact us.


This homepage is maintained by Tom Holoien, Ben Shappee and Kris Stanek. Updated Wed Jul 16 13:05:10 EDT 2014
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