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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"

26418 results found.

  1. Very bright burst detected from SGR 1806-20
  2. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  3. Possible GRB 040903 - further analysis
  4. GRB 040827 - Radio Observations
  5. XMM-Newton Images of GRB 040827
  6. GRB 040827: optical and NIR observations at the VLT
  7. GRB 040827: UKIRT - 2nd epoch K-band imaging
  8. GRB 040827: 2nd epoch of Magellan K-band imaging
  9. GRB 040827: K imaging - no evidence of variability
  10. GRB 040827: Detection of NIR afterglow
  11. GRB040827 XMM-Newton observation
  12. GRB040825A: optical limit before GRB
  13. GRB 040825B: Optical observations
  14. GRB 040827 : Planned XMM-Newton observation
  15. GRB040825B, BVRcIc field photometry
  16. GRB040825A, BVRcIc field photometry
  17. GCN GRB OBSERBATION REPORT
  18. GRB 040825A,optical observations
  19. GRB040825A: optical observations
  20. GRB040825B: optical observations
  21. MASTER: GRB040825b optical observation
  22. GRB 040825: Optical observations
  23. XRF040812: possible afterglow second Chandra observation
  24. GRB 040812: Second epoch CXO Observations
  25. GRB040823,optical observation
  26. XRF040812: GMRT observations
  27. XRF 040812: optical observation at VLT
  28. GRB 040812: Optical counterparts of CXO sources
  29. XRF040812: possible afterglow
  30. CXO observation of GRB 040812
  31. GRB 040812: radio observations
  32. GRB040812, optical/IR observations
  33. GRB 040812: a long GRB detected by INTEGRAL
  34. XRF040701: Optical Observations at ESO
  35. GRB 040730, infrared observations
  36. GRB 040730: a long GRB detected with INTEGRAL
  37. Ongoing activity of SGR 1806-20
  38. GRB040624: optical monitoring at TNG
  39. XRF 040701 - optical observations of the decaying Chandra source
  40. XRF040701: Second-Epoch Chandra Observations
  41. XRF040701: VLA Observations
  42. XRF040701: First-Epoch Chandra Observations
  43. GRB040624, optical observations
  44. GRB040706:observation at University of Miyazaki
  45. Optical Observations of GRB040624
  46. GRB 040624: optical observations at TNG and VLT
  47. MASTER: GRB 040624 optical observation after 0,48d
  48. GRB 040624, optical observations
  49. GRB 040624 - A long GRB detected with INTEGRAL
  50. GRB 030329: Rebrightening of hyperluminal ejecta.
  51. IPN Summary of SGR1806-20 Activity in 2004
  52. SGR 1806-20: no IR variability of the proposed counterparts
  53. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  54. SGR 1806-20, potential NIR counterpart
  55. GRB 040606: Optical observations
  56. MASTER: HETE Alert 3274 optical observation
  57. Activivty of SGR 1806-20
  58. GRB 040511, very fast decay?
  59. GRB 030324: Detection and Color of Host Galaxy
  60. GRB 040511: NIR observations with REM
  61. GRB040511: Candidate optical/NIR afterglow
  62. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  63. GRB 040511: Second Epoch Optical Observations
  64. GRB 040511: Optical observations
  65. GRB 040511: Optical Observations
  66. GRB040511: Optical Observations
  67. GRB040511: Optical Observations
  68. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  69. GRB 040423 (=H3175): A Long GRB Localized by HETE
  70. GRB040422 : I-band follow-up observation at Lulin Observatory
  71. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  72. GRB040422, BVRcIc field calibration
  73. GRB 040422,optical observation
  74. GRB 040422: a long GRB detected with INTEGRAL
  75. GRB 040403, deep optical observations
  76. MASTER: HETE Alert 3163, 3167 technical optical observation
  77. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  78. GRB 040403: Optical observations
  79. GRB 040403: a long GRB detected with INTEGRAL
  80. GRB040323: NIR Observations and Variable Object
  81. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  82. GRB 040323, a dark GRB ?
  83. GRB 040323: a long GRB detected with INTEGRAL
  84. GRB040223: Deep NIR NTT data re-analysis
  85. GRB 040223: XMM-Newton results
  86. GRB040223, improved XMM position
  87. GRB 031203, possible supernova
  88. MASTER: RXTE GRB040308 optical observation
  89. IBAS results on a burst from SGR1806-20
  90. INTEGRAL detection of activity from SGR1806-20
  91. RXTE GRB040229 optical observation: no candidate
  92. GRB 040228 Optical observations
  93. GRB040228 : KISO optical follow-up observation
  94. GRB 040223: Deep NIR NTT observations
  95. GRB 040223 : Optical observation (non-detection)
  96. XMM-Newton Images of GRB 040223
  97. GRB 040223, VLA observations
  98. GRB 040223: REM IJK Observations
  99. GRB 040223 XMM-Newton observation ...
  100. GRB 031203 XMM-Newton observation

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