Recent News

  • No evidence of galaxy-scale hot outflows in two nearby AGN!

    Tuesday, July 3, 2018

    Based on deep Chandra X-ray observations of two nearby AGN (HE0227-0913 and HE0351+0240), M. Powell et al. reported no evidence of galaxy-wide hot gas outflows. After careful analysis of the Chandra PSF to deal with the bright type 1 AGN core, no significant extended emission could be detected. This is a surprising result since current theoretical models predict rather bright X-ray emission from hot gas outflows on kpc-scales powered by the AGN.

    This shows that the prediced outflows are not necessarily ubiquitos in AGN host galaxies. Either the multi-phase gas composition is different than predicited, the AGN is too young to show outflows on large scales, or the AGN is actually not capable of diriving a powerful outflow. Of course, with two objects we cannot systematically explore these effects, but these X-ray observations needed are expensive were done here as a pilot study. We expect that the CARS team is going to obtain additional Chandra observations in the future.

     

    Chandra X-ray images of HE0227-0913 and HE0351+0240 together with their matched simulated PSFs. Below is the X-ray spectrum extracted from the read-out strike that is modelled with a single power-law model.

  • Dimming of Mrk1018 has stopped!

    Wednesday, October 25, 2017

    Our team continued to monitor the changing-look AGN Mrk1018 after its rapid decline. Our new paper led by Mirko Krumpe nicely shows that the dimming of Mrk1018 surprisingly halted by now and has likely reached a minimum in activity. This already rules out some scenarios like a tidal-disruption event. It opens the possibility that Mrk1018 is turning bright again at some point. Our multi-wavelength monitoring of Mrk1018 is therefore continuing and we are expected to present exciting results on this enigmatic AGN in the next years.

    U-band light curve of Mrk1018 after deblending the AGN and host galaxy light using galfit. The strong decline of the changling-look AGN has clearly stopped and shows variabiliy on yearly timescales.

  • 2nd annual meeting of the CARS team

    Thursday, June 1, 2017

    In the week of 29th of May till 2nd of June, 9 brave CARS teamm members met at the Leibniz-Institute for Astrophysics in Potsdam to discuss the progress of the survey, analysis data and preparing upcoming papers. What a productive meeting and a great and enjoyable time for all members of the team. We all thank T. Urrutia and M. Kumpe from the AIP for organizing the fantastic meeting.

    Participants of the CARS team meeting in the front of the 50cm telescope at the AIP.

  • Press releases about extra-ordinary "changing-look" AGN discovery

    Thursday, September 15, 2016

    The publication of the first two CARS papers in A&A about the discovery and nature of the "changing-look" AGN Mrk 1018 are accompanied by several press releases today by ESO, CAASTRO, AIP, and others. The mystery of the rare change in the behaviour of the supermassive black hole at the centre of this distant galaxy has been discovered and solved by the CARS team using ESO’s Very Large Telescope along with the NASA/ESA Hubble Space Telescope and NASA’s Chandra X-ray Observatory. It seems that the black hole has fallen on hard times and is no longer being fed enough fuel to make its surroundings shine.

    The two papers describing the discovery and first detailed investigation of the cause for the dramatic dimming can be found here:

    1) The Close AGN Reference Survey (CARS) - Mrk 1018 returns to the shadows after 30 years as a Seyfert 1, McElroy et al. 2016, A&A, 593, L8

    2) The Close AGN Reference Survey (CARS) - What is causing Mrk 1018’s return to the shadows after 30 years?, Husemann et al. 2016, A&A, 593, L9

     

    For further question please contact either

    Bernd Husemann, European Southern Observatory, bhuseman (AT) eso.org, 0049 89 3200 6750

    Rebecca McElroy, University of Sydney, rmcelroy (AT) physics.usyd.edu.au, 0061 421 882 513

    This image from the SDSS Stripe 82 survey shows the active galaxy Markarian 1018, which has a supermassive black hole at its core. The faint loops of light around the galaxy are a result of its interaction and merger with another galaxy in the recent past. Credit: ESO/CARS survey

  • CARS meets SOFIA for first observations

    Wednesday, March 9, 2016

    Two of the CARS team members recently had the chance to participate on SOFIA science flights in which CARS galaxies are observed with FIFI-LS. PhD student Gerold Busch and CARS team leader Bernd Husemann took-off with SOFIA on March 1 and March 9, respectively, for 10hour long science flights. The Mission: Detecting [CII] in these AGN host galaxies. Despite their low redshift, it is still a challange for SOFIA to get enough signal due to remaining earth atmosphere.  Luckly, [CII] could be detected in the majority of galaxies as planned. Detailed investigations  of the data will start once reduced by the FIFI-LS science teams and we are looking forward for additional data obtained from the southern deployment of SOFIA in Christchurch during July-August.

    Left: CARS team member Gerold Busch in front of SOFIA before departure for an exciting science flight. Right: CARS team leader Bernd Husemann captures in front of the FIFI-LS instrument inside of SOFIA. Both shared the unique experience of flying on this amazing  plane at an altitude of 45000 feet.

  • SOAR Optical/NIR Imaging Approved

    Tuesday, January 12, 2016

    Deep NIR/Optical images were taken at the 4m SOAR telescope at Cerro Paschon, Chile, in September 2015. 14 sources were observed with the SOI optical imager and/or the SPARTAN Near Infrared detector over 4 nights, with 20 minutes of data taken per band for each source. We reached a S/N of 10 or more on the faintest outskirts of the galaxies for each NIR JHK and optical BVR band. Shown below are RGB optical composite images for three of the galaxies. The next SOAR run is scheduled for February 2016, from which we will obtain observations of the remaining galaxies in need of imaging data.

    Composite BVR images of HE 0108-4743, HE 0232-0900, and HE 2211-3903, taken from SOAR in September 2015.

  • CARS 2nd collaboration meeting at ESO

    Friday, February 12, 2016

    From the 9-12th of February the second CARS collaboration meeting was held at ESO in Munich. Many of the team were able to travel to the meeting from as far away as the USA, Australia, and across Europe. Those who were unable to attend joined us over the internet. We had a very productive week working together on material for papers, overviewing our science projects, and outlining action items for this year including observing plans and new observing proposals. With so much fantastic data, and more to come - expect to see some CARS science coming soon to a conference or pre-print archive near you!

    A group photo of those who physically attended the meeting. Back row (left to right): Matthieu Bethermin, Timothy Davis, Gerold Busch, Miguel Perez-Tores, Bernd Husemann. Front row (left to right): Meredith Powell, Tanya Urrutia, Rebecca McElroy. 

  • CARS awarded two nights of GEMINI NIFS time

    Wednesday, December 16, 2015

    We were recently awarded two full nights of NIFS observation time by the GEMINI observatory. Adaptive optics-assisted (laser guide star) near-infrared integral-field spectroscopy in the near-infrared will probe the centres of the galaxies on 100pc scales. Together with the optical MUSE data, which covers the large-scale structure, we will be able to study the signatures and impact of AGN outflows from the core out to the entire host. Furthermore, we will study the circumnuclear star formation history and test theoretical and empirical relations between BH accretion and star formation at small scales.

  • CARS awarded 41 hr of VLA time (2016A)

    Friday, November 13, 2015

    The CARS team was awarded 41 hr of VLA time to study the role of neutral hydrogen in luminous active galaxies. A total of 16 galaxies from our Close AGN Reference Survey will be observed. The observations will provide the deepest H I images ever taken for these luminous nearby AGN down to M(HI)<=1.2e9 Msol/beam. Our observations will allow us to tackle three crucial questions linking luminous AGN and their host galaxies. Namely, we will (i) determine whether suppressed star formation (low H2/HI values), or rather strangulation (high H2/HI values), is at place in nearby luminous AGNs, compared to the non-AGN population at the same stellar mass and morphology stage; (ii) determine what is the dominant gas supply (H2 or HI) for nearby luminous AGN; and (iii) study whether it is AGN feedback, or rather environment, the dominant actor in suppressing star formation.

    The 27 antennas of the VLA will observe during the first semester of 2016 sixteen galaxies of our CARS sample. 

  • 11h of SOFIA observing time granted

    Friday, October 2, 2015

    A relatively big time request of 11 hours was recently granted on the flying observatory SOFIA for Cycle 4 (Feb 2016-Jan 2017). The modified 747-SP hosts a 2.5m telescope that is lifted up more than 40.000 feet  in flight and able to observe the far-IR emission that would otherwise be strongly absorbed by the earth atmosphere. A large suite of instruments can be used onboard of SOFIA and for the CARS project we applied for FIFI-LS time which is a 3D spectrograph operating in the FIR in two channels that allow to observe two FIR emission lines within a 1'x1' large FOV. For CARS we are particularly interested to map the distribution and kinematics of the [CII] 157µm line. We want to test whether [CII] is tracing star formation and what contribution the AGN radiation field has to excite the line. Given that the FOV is exactly matching that of MUSE we can directly compare the light distribution and kinematics of Halpha and [CII] although the spatial resolution in the FIR is 5-10 times worth than in the optical.

    SOFIA Observatory during flight with open doors during a test flight on the 13th July 2010. Source: NASA/Jim Ross

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