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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

20967 results found.

  1. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  2. GRB040916: Optical observations
  3. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  4. GRB040912 (= H3557): Chandra Observations Scheduled
  5. GRB 040912: Optical Observations
  6. GRB/XRF040912,optical observations
  7. GRB 040912, BVRI observations
  8. Optical observations of GRB/XRF 040912 = HETE 3557
  9. Optical observations of field of GRB040912
  10. HETE 3557: Optical observations
  11. GRB 040827 - Radio Observations
  12. GRB040825A: Optical observations
  13. GRB040825A: Optical observations
  14. GRB 040827: optical and NIR observations at the VLT
  15. GRB 040827: 2nd epoch of Magellan K-band imaging
  16. GRB 040827: Detection of NIR afterglow
  17. GRB 040827: Possible detection of optical afterglow
  18. GRB 040827: RTT150 optical observations
  19. GRB 040825B: Optical observations
  20. GRB040827 optical observations
  21. GRB 040825A,optical observations
  22. GRB040825A: optical observations
  23. GRB040825B: optical observations
  24. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  25. GRB 040825A: Optical observations.
  26. GRB040825B: Correction to GCN 2657
  27. GRB 040825: Optical observations
  28. GRB 040812: Second epoch CXO Observations
  29. XRF040812: GMRT observations
  30. XRF 040812: optical observation at VLT
  31. GRB 040812: Optical counterparts of CXO sources
  32. GRB 040812: Keck and LCO optical observations
  33. GRB 040812: Keck and LCO observations
  34. GRB 040812: radio observations
  35. GRB040812, optical/IR observations
  36. GRB 040810: Optical observations of a limited region
  37. XRF040701: Optical Observations at ESO
  38. GRB 040730, infrared observations
  39. GRB 040730: Optical observations
  40. GRB040624: optical monitoring at TNG
  41. XRF 040701 - optical observations of the decaying Chandra source
  42. XRF040701: Second-Epoch Chandra Observations
  43. XRF040701: VLA Observations
  44. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  45. XRF040701: First-Epoch Chandra Observations
  46. GRB040709 J,H-band observations
  47. GRB040624, optical observations
  48. XRF 040701, optical observations
  49. GRB 040624: optical observations
  50. Optical Observations of GRB040624
  51. GRB 040624: optical observations at TNG and VLT
  52. GRB 040624: R-band observations
  53. GRB 040624, optical observations
  54. GRB 030329: Rebrightening of hyperluminal ejecta.
  55. GRB040511: Retraction of redshift identification
  56. SGR 1806-20: no IR variability of the proposed counterparts
  57. SGR 1806-20, potential NIR counterpart
  58. GRB 040606: Optical observations
  59. GRB 040511: NIR observations with REM
  60. GRB 040511: Second Epoch Optical Observations
  61. GRB 040511: Optical observations
  62. GRB 040511: Optical Observations
  63. GRB040511: Optical Observations
  64. GRB040511: Optical Observations
  65. GRB040422: optical observations at Xinglong Observatory
  66. GRB040422: optical observations at CrAO
  67. GRB040422, optical observations at Loiano
  68. GRB040422: optical and NIR observations at the VLT
  69. GRB 040403, deep optical observations
  70. GRB 040403: Optical Observations
  71. GRB 040403 Optical Observations
  72. GRB 040403: Optical observations
  73. GRB 040403: optical observations
  74. GRB 040403: Optical Observations
  75. GRB040323: NIR Observations and Variable Object
  76. GRB 040228 Optical observations
  77. GRB 040223: Deep NIR NTT observations
  78. GRB 040223 : Optical observation (non-detection)
  79. GRB 040223, VLA observations
  80. GRB 040223: REM IJK Observations
  81. GRB031111, optical observations
  82. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  83. GRB031203: Chandra Observations
  84. GRB040106, follow-up radio observations
  85. GRB040106, Radio Observations
  86. GRB040106, likely optical afterglow
  87. GRB040106: Second Epoch Optical Observations
  88. GRB 031220: Optical observations of Chandra X-ray sources
  89. GRB040106: optical observations with REM+ROSS
  90. GRB 040106: Optical observations
  91. GRB031220: Palomar Observations
  92. GRB 031203 I-band monitoring
  93. GRB 2974 follow-up observations
  94. GRB 031203: SMARTS optical monitoring
  95. XMM-Newton Observations of GRB031203: Preliminary Images
  96. GRB 031203: Variable Radio Source
  97. GRB 031203: Magellan spectrum of possible GRB host
  98. GRB 031203: Deep NIR NTT & VLT observations
  99. GRB 031203: Radio detection
  100. GRB 031203: Further reports on December 4 observations

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