1 / 17

Are There Local Analogs of Lyman Break Galaxies?

Are There Local Analogs of Lyman Break Galaxies?. James D. Lowenthal (Smith College/FCAD) R. Nick Durham (Smith College) Brian Lyons (Amherst College) David C. Koo (UCO/Lick Obs.) Matt A. Bershady (U. Wisconsin) Rafael Guzmán (U. Florida) Jesús Gallego (Universidad Complutense de Madrid).

pekelo
Download Presentation

Are There Local Analogs of Lyman Break 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. Are There Local Analogs of Lyman Break Galaxies? James D. Lowenthal (Smith College/FCAD) R. Nick Durham (Smith College) Brian Lyons (Amherst College) David C. Koo (UCO/Lick Obs.) Matt A. Bershady (U. Wisconsin) Rafael Guzmán (U. Florida) Jesús Gallego (Universidad Complutense de Madrid) See also: Jason Melbourne (AO) Matt Bershady (internal kinematics) David Koo (z~1) Drew Phillips ([O/H]) Kai Noeske (UDF profiles)

  2. Big question: How do Lyman break galaxies fit into galaxy formation/evolution? • Specific motivating questions: • What are detailed characteristics of LBGs? • Range of LBG masses? • Do LBGs reside in much larger, more massive halos, or is it “what-you-see-is-what-you-get”, i.e., dwarf starburst galaxies? • What constraints can we place on LBG “host galaxy” type? • One approach: find local analogs -- easier to study in detail. Then compare to LBGs.

  3. Basic parameters of Lyman break galaxies

  4. Lyman Break Galaxy Examples 10” Lowenthal et al. 1997

  5. Possible best local analogs to LBGs: HII galaxies and luminous blue compact galaxies (LBCGs)

  6. LCB Galaxy Examples z<0.05 z~0.75 10 kpc 6” WIYN R-band (Pisano et al. 2001) HDF-FF I814 (Phillips et al. 1997)

  7. HST/STIS images in rest-UV of HII Galaxies and LCBGs Goal: Compare local starburst and high-redshift LBG samples at same rest-UV wavelength • 12 (HII) galaxies from UCM survey (z~0): STIS/FUV images • 14 LCBGs from Kitt Peak Galaxy Redshift Survey (z~0.5): STIS/NUV images

  8. STIS FUV images z~0 sample Morphologies: VERY diverse, disturbed, multiple knots 6.5”

  9. STIS NUV images z~0.75 sample Morphologies: more disturbed, multiple knot systems 3.75”

  10. Rest-UV Asymmetries Measure image asymmetry A following Conselice et al. (2000)

  11. Rest-UV Asymmetries Large range in A; spans median for LBGs LBG median

  12. What would LCBGs and HII galaxies look like at z~3? • Simulate z=3 HDF view: • Rebin STIS images • Add noise to match S/N at z=3 • Low redshift sample not visible at z=3 (but barely visible in ACS/GOODS/UDF) • z~0.75 sample all visible at z=3; morphologies much simpler, more compact; low-SB structure lost.

  13. True z STIS vs. simulated HDF True z Simulated HDF z=3

  14. Rest-UV Asymmetries of simulated z=3 view

  15. Asymmetry affected by z? Asymmetries drop with redshift as faint outer regions fade

  16. True z vs. simulated z=3 asymmetries Median asymmetry in z=3 simulation: Amed<0.1 (vs. 0.3 for original images)

  17. Conclusions • HIIGs and LCBGs are smaller, lower-L than LBGs, but with similar morphologies, asymmetries, colors, star formation properties. • Masses of HIIGs and LCBGs are small, M<1010 M; many LBGs may be too. • Caveats: Fate of LBGs not known; difficult to constrain masses of LBGs for comparison • Still to come: better morphological analysis (e.g., Gini coefficient, Lotz et al. 2004)

More Related