1 / 14

Gravitational lensing and the problem of faint galaxies

Gravitational lensing and the problem of faint galaxies. Alicia Berciano Alba (JIVE / Kapteyn institute) Mike Garret (JIVE) Leon Koopmans (Kapteyn institute). The problem of sub-mm Galaxies. Hughes et al. (Nature 1998). Nature of sub-mm galaxies.

odell
Download Presentation

Gravitational lensing and the problem of faint galaxies

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Gravitational lensing and the problem of faint galaxies Alicia Berciano Alba (JIVE / Kapteyn institute) Mike Garret (JIVE) Leon Koopmans (Kapteyn institute)

  2. The problem of sub-mm Galaxies Hughes et al. (Nature 1998)

  3. Nature of sub-mm galaxies SCUBA sources = faint dusty star forming galaxies at high z obscured in optical but not in sub-mm and radio At low z  rare objects (M82, Arp220) At high z  the peak is shifted from FIR to sub-mm electrons die like SN Massive stars a lot of dust A lot of uv-radiation FIR Emission

  4. Solution: Gravitational lensing as a telescope If we are lucky… very massive object Between sub-mm source and us several images with magnification in size and flux density we can “see” the iceberg below the sea strong GL effect YES, we are : Abell 2218 GL in clusters of galaxies MS0451.6-0305

  5. Abell 2218 Sources: Star forming galaxy (z=2.516)  3 images arc#289(Z=1.034) arc#289 Kneib et al. (2004) Data: Optical images (HST) NIR imagin / spectroscopy (WHT/ Keck) Sub-mm (SCUBA 850 mm) Radio (VLA 8.2 GHz / WSRT 1.4 GHz) Kneib et al. (2004) Knudsen (2004) Sheth et al. (2004) Garrett et al. (2005)

  6. MS0451.6-0305 Borys et al. (2004) DATA - Optical image (HST) - VLT (Very Large Telescope) spectrocopy - Sub-mm (SCUBA 850 mm)  solid line - X-ray (Chandra)  dotted line - X-ray point sources (Molar et al. 2002)  croses - NIR (Near Infra-Red) objects  circles SOURCES - 2 lens images of a fold arc (ARC1)  LBG - 3 lens images of 2 objects (B/C)  2 EROs - P  very blue object

  7. Trying to find the radio counterpart… Cluster´s centre • Data • From VLA archive • Freq = 1.36 GHz (L-band) AB config. • Obs time (”on-source” ) = 7h 46min • 1s rms = 9 mJy / beam

  8. The • Comparison • Between • Sub-mm • and • radio alineation problem • Radio emission is coincident with the sub-mm emission & extended on the same angular scale. • Radio & sub-mm emission due to the same source(s) • Two emissions magnified by GL effect • Radio  St > 100 mJy (few tens mJy) • Sub-mm  St >>10 mJy (few mJy) • S850 mm / S1.4 Ghz ~ 100  as we expect

  9. Borys et al. conclusions ARC1 (LBG) • Sources of sub-mm emission B/C pair (EROs) 2/3 of the total flux • Borys et al. can´t • reproduce • the sub-mm emission!!!

  10. OurpreliminarResults • B1/C1 at the edge of the radio emission  maybe not related with the emissions? • We can explain the elongation in the top of sub-mm emission  new radio source • We can explain the gap in the borys simulation  3 new radio sources • No radio detection in B3/C3  is not a surprise

  11. Future Work • Obtain the HST and SCUBA images from Borys to make a correct alignament with the radio image • know the error positions of ARC1 and EROs • Try to reproduce the detailed morphology of the radio map with a similar simulation used by Borys • Understand what´s going on with the radio image in terms of lensing model • Make a tapered low resolution and higher resolution uniformly weighted image of the radio data • Look for more data in the VLA rachive (5 and 8 GHz) • Apply for VLA data in A configuration  1” resolution (instead of the actual 5” resolution)

  12. Conclusions • We detect the second multiply imaged radio emission associated with massive cluster lensing • We find 1 radio source to explain the the excess of scuba emission in the top left part of the image • We find 3 radio sources to explain the gap in Bory´s simulation • We can´t be sure about the contribution of the B/C pair in the radio and sub-mm emissions The answer (I hope) in the next meeting…

  13. Summary The only way to detect this sources is through the GL effect • We have 2 systems with sub-mm and radio to study their nature  we are looking for more • We must finish the analysis of radio data in MS0451.6-0305 • The case of MS0451.6-0305 is more complex than A2218  we need better radio images to know the nature of the sub-mm emmision

More Related