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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"

15985 results found.

  1. GRB 041006: Optical decay
  2. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  3. GRB041006: Fading of optical afterglow candidate
  4. GRB 041006 : Optical follow-up observation at KISO
  5. GRB 041006: Finding chart
  6. GRB 041006: Optical afterglow candidate
  7. GRB 040924: Second Epoch WSRT Radio Observations
  8. radio observations, GRB 040924
  9. GRB040929,optical observation
  10. GRB040929: MASTER optical observations
  11. GRB040924,optical observation
  12. GRB040924, RTT150 optical observation
  13. GRB040924,optical observation
  14. GRB040924, RTT150 optical observation
  15. GRB040924: Afterglow magnitude at t=17.5hr
  16. GRB 040924: WSRT Radio Observations
  17. GRB040924 : Optical candidate observations at Lulin observatory
  18. GRB040924 : Optical candidate observations at Lulin observatory
  19. GRB 040924: Subaru NIR observation
  20. GRB040924: Optical afterglow properties
  21. GRB 040924: RTT150 optical observations
  22. GRB 040924, optical follow-up
  23. GRB040924: MASTER: OT decay
  24. GRB040924: MASTER Optical observations
  25. IPN triangulation of GRB040924 (H3564)
  26. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  27. GRB040924 (H3564): Optical afterglow candidate
  28. XRF 040916: Radio Observations
  29. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  30. XRF040916: continuing decay of OT
  31. GRB040912(=H3557): Candidate Optical Afterglow
  32. XRF040916, optical observations
  33. XRF040916: Optical Transient Candidate by Subaru
  34. GRB040916 optical limits 17 min after GRB
  35. XRF 040912, identification of CXO sources
  36. XRF 040912 (=H3557): Spectral and Temporal Properties
  37. XRF040916: optical follow-up observations
  38. GRB040916: Archival optical observations
  39. XRF 040916, optical follow-up
  40. GRB040916: Optical observations
  41. GRB040916 (= H3558): Improved Localization from HETE WXM
  42. GRB040916 (= H3558): A Long XRF Localized by HETE
  43. GRB040912 (= H3557): Chandra Observations Scheduled
  44. GRB 040912: Optical Observations
  45. GRB/XRF040912,optical observations
  46. Optical observations of GRB/XRF 040912 = HETE 3557
  47. GRB040912 : Kiso Optical follow-up observation
  48. Optical observations of field of GRB040912
  49. HETE 3557: Optical observations
  50. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  51. GRB040827: analysis of the XMM-Newton observation
  52. GRB040825A: Optical observations
  53. GRB040825A: Optical observations
  54. GRB 040827: optical and NIR observations at the VLT
  55. GRB 040827: Detection of NIR afterglow
  56. GRB 040827: Possible detection of optical afterglow
  57. GRB 040827: RTT150 optical observations
  58. GRB040825A: optical limit before GRB
  59. MASTER: GRB040827 possible OT
  60. GRB 040825B: Optical observations
  61. GRB040827 optical observations
  62. GRB 040825A,optical observations
  63. GRB040825A: optical observations
  64. GRB040825B: optical observations
  65. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  66. GRB 040825A: Optical observations.
  67. MASTER: GRB040825a optical observation
  68. MASTER: GRB040825b optical observation
  69. GRB 040825: Optical observations
  70. GRB040823,optical observation
  71. XRF 040812: optical observation at VLT
  72. GRB 040812: Optical counterparts of CXO sources
  73. CXO observation of GRB 040812
  74. GRB 040812: Keck and LCO optical observations
  75. GRB040812, optical/IR observations
  76. GRB 040810: Optical observations of a limited region
  77. XRF040701: Optical Observations at ESO
  78. GRB 040730: Optical observations
  79. GRB040624: optical monitoring at TNG
  80. XRF 040701 - optical observations of the decaying Chandra source
  81. GRB040624, optical observations
  82. XRF 040701, optical observations
  83. XRF040701 (=U11548): a bright XRF detected by HETE
  84. GRB 040624: optical observations
  85. Optical Observations of GRB040624
  86. GRB 040624: optical observations at TNG and VLT
  87. MASTER: GRB 040624 optical observation after 0,48d
  88. GRB 040624: R-band observations
  89. GRB 040624, optical observations
  90. GRB 030329: Rebrightening of hyperluminal ejecta.
  91. GRB040511: Retraction of redshift identification
  92. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  93. GRB 040606: Optical observations
  94. MASTER: HETE Alert 3274 optical observation
  95. GRB 040511: NIR observations with REM
  96. GRB 040511: Optical limit
  97. GRB040511: Candidate optical/NIR afterglow
  98. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  99. GRB 040511: Second Epoch Optical Observations
  100. GRB 040511: Optical observations

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