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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"

15980 results found.

  1. GRB 041006: Optical afterglow candidate
  2. GRB 040924: Second Epoch WSRT Radio Observations
  3. radio observations, GRB 040924
  4. GRB040929,optical observation
  5. GRB040929: MASTER optical observations
  6. GRB040924,optical observation
  7. GRB040924, RTT150 optical observation
  8. GRB040924,optical observation
  9. GRB040924, RTT150 optical observation
  10. GRB040924: Afterglow magnitude at t=17.5hr
  11. GRB 040924: WSRT Radio Observations
  12. GRB040924 : Optical candidate observations at Lulin observatory
  13. GRB040924 : Optical candidate observations at Lulin observatory
  14. GRB 040924: Subaru NIR observation
  15. GRB040924: Optical afterglow properties
  16. GRB 040924: RTT150 optical observations
  17. GRB 040924, optical follow-up
  18. GRB040924: MASTER: OT decay
  19. GRB040924: MASTER Optical observations
  20. IPN triangulation of GRB040924 (H3564)
  21. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  22. GRB040924 (H3564): Optical afterglow candidate
  23. XRF 040916: Radio Observations
  24. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  25. XRF040916: continuing decay of OT
  26. GRB040912(=H3557): Candidate Optical Afterglow
  27. XRF040916, optical observations
  28. XRF040916: Optical Transient Candidate by Subaru
  29. GRB040916 optical limits 17 min after GRB
  30. XRF 040912, identification of CXO sources
  31. XRF 040912 (=H3557): Spectral and Temporal Properties
  32. XRF040916: optical follow-up observations
  33. GRB040916: Archival optical observations
  34. XRF 040916, optical follow-up
  35. GRB040916: Optical observations
  36. GRB040916 (= H3558): Improved Localization from HETE WXM
  37. GRB040916 (= H3558): A Long XRF Localized by HETE
  38. GRB040912 (= H3557): Chandra Observations Scheduled
  39. GRB 040912: Optical Observations
  40. GRB/XRF040912,optical observations
  41. Optical observations of GRB/XRF 040912 = HETE 3557
  42. GRB040912 : Kiso Optical follow-up observation
  43. Optical observations of field of GRB040912
  44. HETE 3557: Optical observations
  45. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  46. GRB040827: analysis of the XMM-Newton observation
  47. GRB040825A: Optical observations
  48. GRB040825A: Optical observations
  49. GRB 040827: optical and NIR observations at the VLT
  50. GRB 040827: Detection of NIR afterglow
  51. GRB 040827: Possible detection of optical afterglow
  52. GRB 040827: RTT150 optical observations
  53. GRB040825A: optical limit before GRB
  54. MASTER: GRB040827 possible OT
  55. GRB 040825B: Optical observations
  56. GRB040827 optical observations
  57. GRB 040825A,optical observations
  58. GRB040825A: optical observations
  59. GRB040825B: optical observations
  60. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  61. GRB 040825A: Optical observations.
  62. MASTER: GRB040825a optical observation
  63. MASTER: GRB040825b optical observation
  64. GRB 040825: Optical observations
  65. GRB040823,optical observation
  66. XRF 040812: optical observation at VLT
  67. GRB 040812: Optical counterparts of CXO sources
  68. CXO observation of GRB 040812
  69. GRB 040812: Keck and LCO optical observations
  70. GRB040812, optical/IR observations
  71. GRB 040810: Optical observations of a limited region
  72. XRF040701: Optical Observations at ESO
  73. GRB 040730: Optical observations
  74. GRB040624: optical monitoring at TNG
  75. XRF 040701 - optical observations of the decaying Chandra source
  76. GRB040624, optical observations
  77. XRF 040701, optical observations
  78. XRF040701 (=U11548): a bright XRF detected by HETE
  79. GRB 040624: optical observations
  80. Optical Observations of GRB040624
  81. GRB 040624: optical observations at TNG and VLT
  82. MASTER: GRB 040624 optical observation after 0,48d
  83. GRB 040624: R-band observations
  84. GRB 040624, optical observations
  85. GRB 030329: Rebrightening of hyperluminal ejecta.
  86. GRB040511: Retraction of redshift identification
  87. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  88. GRB 040606: Optical observations
  89. MASTER: HETE Alert 3274 optical observation
  90. GRB 040511: NIR observations with REM
  91. GRB 040511: Optical limit
  92. GRB040511: Candidate optical/NIR afterglow
  93. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  94. GRB 040511: Second Epoch Optical Observations
  95. GRB 040511: Optical observations
  96. GRB 040511: Optical Observations
  97. GRB040511: Optical Observations
  98. GRB040511: Optical Observations
  99. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  100. Type Ic SN2001em (off-axis GRB jet?), optical spectrum

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