1 / 19

HEROs in an Overdense Region at z=2.4

HEROs in an Overdense Region at z=2.4. Myungshin Im (Seoul National University) & IRAC GTO team (PI: G. Fazio) Partial List of Collaborators: M. Pahre, H. Smith, S. Willner (SAO) + IRAC GTO. M. Lacy, F. Marleau, D. Fadda (SSC). What is HERO?.

ardara
Télécharger la présentation

HEROs in an Overdense Region at z=2.4

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. HEROs in an Overdense Region at z=2.4 Myungshin Im (Seoul National University) & IRAC GTO team (PI: G. Fazio) Partial List of Collaborators: M. Pahre, H. Smith, S. Willner (SAO) + IRAC GTO. M. Lacy, F. Marleau, D. Fadda (SSC).

  2. What is HERO? According to the Cambridge International Dictionary of English, Hero, female also heroine (PERSON) noun[C] a person who is admired for having done something very brave or having achieved something great, or the main character in a book, film or play, esp., one who is admired for their good qualities. Hero, submarine sandwich (FOOD), noun[C] AMERICAN a long thin sandwich filed with cold meat, cheese, and salad. HERO, (OBJECT), noun[C] ASTRONOMY acronym for “Hyper Extremely Red Objet”. An astronomical object (very possibly a galaxy) which is invisible in the optical, and has a very red near-infrared (NIR) color (J-K > 3, Totani et al. 2001). ? August 2005, Lijiang, Extreme Starburst

  3. Actually, a Member of ERO (Extremely Red Object) Family… • (Normal) ERO: Optical – NIR Color Selected EROs (R-K > 5, I-K > 4 mag) – z > 1 • HERO (Hyper ERO): J-K > ~ 3.0 (Totani et al. 2001; Im et al. 2002) – z > 2.4 • IERO (IR-Selected ERO): IRAC-Color Selected EROs (Yan et al. 2004). • NERO (NIR-Selected ERO): J-K Red Galaxies – z > 1.5-2.0

  4. HERO (Hyper Extremely Red Object) J-K >~3mag z=2-3 old galaxy or z=2-3 dusty galaxy or z=10-13 LBG. Im et al. (2002) August 2005, Lijiang, Extreme Starburst

  5. Old Galaxy at High Redshift ERO Study was originally aimed to search for high-z massive, early-types. August2005, Lijiang, Extreme Starburst

  6. Young and Dusty Galaxy (Extreme Starburst?!) But, people realized that ERO population include many dusty starforming galaxies (~ 50%, e.g., Yan et al. 2004). August 2005, Lijiang, Extreme Starburst

  7. Infant Galaxy Shortly After Big Bang August 2005, Lijiang, Extreme Starburst

  8. Galaxy Formation in CDM Universe • Is is true that there are • very few massive, old • galaxies at high redshift? 2. When is the formation epoch of massive, old galaxies? 3. Is there any dependence on environment? (early formation in cluster?) Predictions: Fewer massive early-types at higher redshift. Earlier formation of massive objects in cluster environment.  Need for HEROs August 2005, Lijiang, Extreme Starburst

  9. 53W002 Field • 53W002 is a radio galaxy at z=2.4. • Lyman-alpha emitters at z ~ 2.4 in the vicinity of • 53W002 (Keel et al. 1999; Pascarelle et al. 1996; • Windhorst et al. 1997)  z=2.4 cluster of galaxies? • Recent observations reveal that this field contain • other interesting objects, such as submm galaxies • (Smail et al. 2002), and dozens of HEROs • (Hyper Extremely Red Objects; Im et al. 2002). Is this a high-z galaxy cluster? When did early-type galaxies form in cluster environment?

  10. Color-Magnitude Relation Im et al. (2005), from Palomar 5-m WIRC Obs. Z=3 Z=2 3 2.7 2 J-K Z=1 20 22 K August 2005, Lijiang, Extreme Starburst

  11. 53W002 vs. CDF-South 53W002 CDF-S J-K K (Vega) K (Vega) 18 vs 2 August 2005, Lijiang, Extreme Starburst

  12. Redshift Distribution(53W002) Overdensity at z ~ 2.4 ! (Keck LRIS-B: Colbert & Malkan 2005) August 2005, Lijiang, Extreme Starburst

  13. Spitzer Observation of the 53W002 Field (M. Pahre) 1 Hour Exposure in Each Passband (3.6, 4.5, 5.6, 8 micron). Field of View: 5x5 sq. arcmin. Sensitivity: 1 m Jy at 3.6 & 4.5 microns, 5 m Jy otherwise.

  14. Palomar WIRC Image (K, 2’ by 2’ Zoom-In) Green Circle: 53W002_HERO1 with K=21.5 mag 7 hrs on 5-m

  15. Spitzer IRAC Image (2’ by 2’ Zoom-In) 1 hr on 0.85m

  16. SED of HEROs 1 (Old or Dusty Galaxy at z ~ 2.4 • SED of the HERO is consistent with a moderately old galaxy at z ~ 2.4 • Stellar Mass of this object could be 1012 M_sun (Similar to Massive Galaxies at z=0 (Im et al. 2005, in preparation).

  17. SED of HEROs 2: AGN?

  18. SED of Lyman-alpha Emitters (z ~ 2.4) Submm 53W002 Fnu (uJy) Starforming Wavelength (micron)

  19. Conclusions • HEROs: -Not Lyman-break galaxies at z ~ 12. -Massive Red galaxies at z ~ 2.4 -Old or Dusty? Not Clear Yet. -Age > a few hundred Myrs (dusty). Age > 1Gyr (old) -E-like (3/11), AGN-like (3/11), Intermediate (5/11). • Lyman-alpha emitters: AGN or Young Gs (~ 50 – 100 Myr). • Spitzer Cycle 2 observation (MIPS 24) is underway to determine how dusty these HEROs and Lyman-alpha emitters are.

More Related