1 / 21

The SEDs of Interacting Galaxies

The SEDs of Interacting Galaxies. NGC 520: NUV, 3.6 µ m , & 8.0 µ m. Lauranne Lanz Nicola Brassington , Andreas Zezas , Howard A. Smith, Matthew L. N. Ashby, Elisabete da Cunha, Christopher Klein, Patrik Jonsson , Chris Hayward Lars Hernquist , Giovanni Fazio

bijan
Download Presentation

The SEDs of Interacting 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. The SEDs of Interacting Galaxies NGC 520: NUV, 3.6 µm, & 8.0 µm Lauranne Lanz Nicola Brassington, Andreas Zezas, Howard A. Smith, Matthew L. N. Ashby, Elisabeteda Cunha, Christopher Klein, PatrikJonsson, Chris Hayward Lars Hernquist, Giovanni Fazio Harvard-Smithsonian Center for Astrophysics llanz@cfa.harvard.edu L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  2. Outline • What is Spitzer Interacting Galaxy Survey (SIGS)? • SED shapes • SED fitting • sSFR comparisons • Trends with interaction stage N3226-N3227 3.6 µm, 4.5 µm, & 8 µm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  3. Sample Selection • Keel-Kennicutt(Keel et al. 1985) “complete” and “Arp” samples: • Selected based on association likelihood • Require |Δv|< 600 km s-1 to remove non-associated pairs • Imposed distance constraint cz < 4000 km s-1 • Resulting sample: 111 galaxies in 50 systems NGC 2976: NUV, 3.6 µm, & 8.0 µm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  4. Observations • Complete Spitzer coverage: • IRAC, MIPS, and nuclear IRS spectra • Almost complete GALEX coverage • Some Herschel coverage • Ancillary data • WISE coverage • Some Chandra/XMM coverage • Hα fluxes M51 NUV, IRAC 3.6 µm, & SPIRE 250 µm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  5. Sample Selection and Observation Set Benefits • Not morphologically selected: large range of interaction parameters • Not infrared selected: less active systems included • Not based on optical line diagnostics • UV and IR coverage gives complete SFR NGC 520: NUV, 3.6 µm, & 8.0 µm NGC 470 & NGC 474: FUV, 3.6 and 4.5 µm, & 8.0 µm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  6. Example: M51 and NGC 3430/3424 IRAC 3.6 µm, 4.5 µm, 8 µm 2MASS J, H, Ks GALEX FUV NUV SPIRE 250 µm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  7. Photometry • S-Extractor used to determine NUV and 3.6 µm apertures IRAC 3.6 µm, 4.5 µm, 8 µm 2MASS J, H, Ks GALEX FUV NUV SPIRE 250 µm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  8. Photometry • S-Extractor used to determine NUV and 3.6 µm apertures • Fluxes determined in larger aperture in all bands • Uncertainty: Calibration and Poisson IRAC 3.6 µm, 4.5 µm, 8 µm 2MASS J, H, Ks GALEX FUV NUV SPIRE 250 µm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  9. SED shapes M51 A M51 B Log( νLν / L) Log( νLν / L) NGC 3424 NGC 3430 Log( νLν / L) Log( νLν / L) L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  10. Two blackbodies + β=1.5 graybody M51 A M51 B 4367 K 356.2 K 28.6 K 4058 K 357.1 K 25.8 K Log( νLν / L) Log( νLν / L) NGC 3424 NGC 3430 3572 K 303.5 K 29.2 K 3307 K 339.5 K 25.2 K Log( νLν / L) Log( νLν / L) L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  11. MagPhys SED-fitting Code • Optical stellar from Bruzual & Charlot 2003 and infrared dust from da Cunha, Charlot, & Elbaz 2008 spectral libraries • Energy absorbed in UV/optical is re-emitted in IR • No AGN contribution considered • Likelihood distributions constructed for model parameters to determine best fit SED Elisabeteda Cunha’s talk this afternoon L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  12. Fit SEDs sSFR Log( λLλ / L) Tcold Twarm sSFR Log( λLλ / L) Tcold Twarm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  13. Fit SEDs sSFR Log( λLλ / L) Tcold Twarm sSFR Log( λLλ / L) Tcold Twarm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  14. Fit comparisons TWarm FIR β=1.5 gray-body temperature falls between SED-fitted warm and cold temperatures TSED / K TCold TGraybody/ K Frac. Difference Log( L8-1000µm,3part/ L) Log( LDust,SED / L) The integrated 8-1000 µm 3-component fit agrees well with the dust luminosity determined from fitting the SED. L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  15. Comparison of Specific Star Formation Rates N 3430 M51A Log(sSFR/yr-1) Prescription Log(sSFR/yr-1) SED Fitting L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  16. Trends with Interaction Stage L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  17. Trends with Interaction Stage L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  18. Trends with Interaction Stage L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  19. Summary • SIGS will provide a sample of interacting galaxies from first pass to coalescence with a range of interaction parameters. IC 1801 and NGC 935 NUV, 3.6 and 4.5 µm, & 8.0 µm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  20. Summary • With the first 10 groups with SPIRE data, we: • find a range of SED shapes, especially in the ratio of MIR to optical/UV. • measured sSFR and temperatures using the MagPhys (da Cunha et al. 2008) SED-fitting code. • find an increase in warm component temperature with interaction stage, but no significant change in sSFR. M81: NUV, 8.0 µm, & 250 µm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

  21. Thank you for the attention and stay tuned for more: • 40 more interacting groups • Nuclear activity • Comparison with simulated systems M101: NUV, 3.6 µm, & 8 µm Cox et al. 2006 N3448 – U6016: FUV, 3.6 µm, 4.5 µm, & 8 µm L. Lanz, Harvard-CFA, SED2011 Sept. 6, 2011

More Related