• Sedgwick, Chris (Department of Physical Sciences, The Open University) ;
  • Serjeant, Stephen (Department of Physical Sciences, The Open University) ;
  • Pearson, Chris (RAL Space, Rutherford Appleton Laboratory) ;
  • Takagi, Toshinobu (Institute of Space and Astronautical Science, JAXA) ;
  • Matsuhara, Hideo (Institute of Space and Astronautical Science, JAXA) ;
  • Wada, Takehiko (Institute of Space and Astronautical Science, JAXA) ;
  • Lee, Hyung Mok (Department of Physics and Astronomy, Seoul National University) ;
  • Im, Myungshin (Department of Physics and Astronomy, Seoul National University) ;
  • Jeong, Woong-Seob (Korea Astronomy & Space Science Institute) ;
  • Oyabu, Shinki (Graduate School of Science, Nagoya University) ;
  • White, Glenn J. (Department of Physical Sciences, The Open University)
  • Received : 2012.07.01
  • Accepted : 2012.08.15
  • Published : 2012.09.16


This paper presents $H{\alpha}$ emission line detections for four galaxies at z > 3.5 made with AKARI as part of the FUHYU mission program. These are the highest-redshift $H{\alpha}$ detections to date in star-forming galaxies. AKARI's unique near-infrared spectroscopic capability has made these detections possible. For two of these galaxies, this represents the first evidence of their redshifts and confirms their physical association with a companion radio galaxy. The star formation rates (SFRs) estimated from the $H{\alpha}$ lines under-predict the SFRs estimated from their far-infrared luminosities by a factor of ~ 2 - 3. We have also detected broad $H{\alpha}$ components in the two radio galaxies which indicate the presence of quasars.


Supported by : NRFK


  1. De Breuck, C., et al., 2001, Spectroscopy of Ultra- Steep-Spectrum Radio Sources, AJ, 121, 1241
  2. Ivison, R. J., et al., 2008, Interferometric Imaging of the High-Redshift Radio Galaxy 4C60.07, MNRAS, 390, 1117
  3. Kennicutt, R. C. Jr., 1998, Star Formation in Galaxies along the Hubble Sequence, ARA&A, 36, 189
  4. Negrello, M., et al., 2009, Photometric Redshift Accuracy in AKARI Deep Surveys, MNRAS, 394, 375
  5. Onaka, T., et al., 2007, The Infrared Camera (IRC) for AKARI, PASJ, 59S, 401
  6. Onaka, T., et al., 2009, AKARI IRC Data User Manual for Post-Helium (Phase 3) Mission, Version 1.1
  7. Pearson, C. P., et al., 2010, The AKARI FUHYU Galaxy Evolution Program: First Results from the GOODS-N Field, A&A, 514, A9
  8. Roettgering, H. J. A., et al., 1997, Spectroscopy of Ultra-Steep Spectrum Radio Sources: a Sample of z > 2 Sources, A&A, 326, 505
  9. Serjeant, S., et al., 2009, AKARI Detections of Submm Galaxies and Vice Versa, ASPC, 418, 339
  10. Serjeant, S., et al., 2008, SHADES - IX. The Environment, Mass and Redshift Dependence of Star Formation, MNRAS, 386, 1907
  11. Stevens, J. A., et al., 2003, The Formation of Cluster Elliptical Galaxies as Revealed by Extensive Star Formation, Nature, 425, 264
  12. Swinbank, A. M., et al., 2004, The Rest-Frame Optical Spectra of SCUBA Galaxies, ApJ, 617, 64