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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"
  1. GRB 090715: Swift detection of a short hard burst
  2. Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
  3. Swift satellite anomaly
  4. GRB090713 optical limit by "Pi of the Sky"
  5. GRB 090712: Fermi GBM observation
  6. GRB 090713: Fermi GBM detection
  7. GRB 090712: Swift-BAT refined analysis
  8. GRB 090712: Swift detection of a burst
  9. GRB 090709A: Xinglong TNT optical upper limit
  10. VLA radio observations of GRB 090709A
  11. GRB 090621B: MTM-500 optical observations
  12. GRB 090709A: deep optical observation with the 10.4m GTC
  13. GRB090709A : WSRT Radio observation
  14. GRB 090709A: Suzaku WAM observation of the prompt emission
  15. GRB 090709A: Swift UVOT upper limits
  16. GRB 090709A: WHT LIRIS observations
  17. GRB 090709B: Fermi GBM detection
  18. GRB 090709A: confirmation of the periodicity in the SPI-ACS data
  19. GRB 090709A: evidence for a very red afterglow at low z
  20. Konus-Wind and Konus-RF observations of GRB 090709A
  21. GRB 090709A: P60 Observations
  22. GRB 090709A: Quasiperiodic variations in the BAT light curve
  23. GRB 090709A: NOT optical observations
  24. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  25. GRB 090709A: Swift XRT Refined Analysis
  26. GRB 090709B, Swift-BAT refined analysis
  27. GRB 090709A: Swift-BAT refined analysis
  28. GRB090709A: High Energy BAT/XRT Analysis Suggests Low to Moderate Redshift
  29. GRB 090709A: Wyoming Infrared Observatory NIR upper limits
  30. GRB 090709A, RIMOTS optical upper limits
  31. GRB 090709A: Enhanced Swift-XRT position
  32. GRB 090709A - PAIRITEL Discovery of a Red Afterglow
  33. GRB 090709A: Subaru NIR observation
  34. GRB 090709B: Swift detection of a burst
  35. GRB 090709 : planned Suzaku-ToO observation
  36. GRB 090708 : Fermi GBM detection
  37. GRB 090709: Faulkes Telescope North Upper Limits
  38. GRB 090626: Suzaku WAM observation of the prompt emission
  39. GRB 090709: PAIRITEL NIR Upper Limits
  40. GRB 090704: Fermi GBM observation
  41. GRB 090709: ROTSE-III Optical Limits
  42. GRB 090709: Swift detection of a bright burst
  43. GRB 090708: Early RAPTOR Optical Limits
  44. GRB 090708, Swift-BAT refined analysis
  45. GRB 090708: ROTSE-III Optical Limits
  46. GRB 090708: Swift detection of a burst
  47. GRB 090704: a long GRB found in INTEGRAL off-line analysis
  48. GRB 090706: Fermi GBM detection
  49. Swift-BAT trigger 356516 is not a GRB
  50. Possible GRB090705: Swift-XRT observations
  51. GRB 090705: PAIRITEL NIR Observations
  52. GRB 090705: Swift detection of a possible burst
  53. XRF 090702 : RTT150 optical observations
  54. GRB 090618: Mondy optical observations
  55. GRB 090529: CrAO optical upper limit
  56. GRB 090529: MTM-500 optical observations
  57. GRB 090529: Mt.Terskol optical observations
  58. XRF 090702: Swift-XRT refined analysis
  59. GRB 090703: Fermi GBM detection
  60. GRB 090702: UVOT upper limits
  61. GRB 090313: optical observations
  62. XRF 090702: VLT imaging
  63. XRF 090702: Swift-XRT afterglow position
  64. XRF 090702: a long soft GRB localized with INTEGRAL
  65. GRB 090404: Deep optical imaging and possible host association (correction)
  66. GRB 090404: Deep optical imaging and possible host association
  67. GRB 090701: Fermi GBM detection
  68. GRB 090628: Swift XRT refined analysis
  69. GRB 090630: Fermi GBM detection
  70. GRB 090618: RTT150 optical observations
  71. GRB 090628: Swift/UVOT Upper Limits
  72. Konus-Wind observation of GRB 090626
  73. GRB080628: SAO RAS optical observations
  74. GRB 090628: Swift-BAT refined analysis
  75. GRB090618: 15GHz radio emission faded
  76. GRB 090628: GROND upper limits
  77. GRB 090628: Enhanced Swift-XRT position
  78. GRB 090628: 1.23m CAHA optical observations
  79. GRB 090626: IPN localization
  80. GRB 090628: Swift/UVOT Finding Chart Observation
  81. GRB 090628: Swift XRT position
  82. GRB 090628: Swift detection of a burst
  83. Fermi LAT observations of GRB 090626
  84. GRB 090625B: Fermi GBM observation
  85. GRB 090423: Spitzer observations of the z~8.3 burst
  86. GRB 090625B: Swift/UVOT Upper Limits
  87. GRB 090625B: Swift-XRT refined analysis
  88. GRB 090626: Fermi GBM detection
  89. GRB 090625B: GROND upper limits
  90. GRB 090623: Suzaku WAM observation of the prompt emission
  91. GRB090618: HCT optical observations
  92. GRB 090618: SARA Second Epoch Observations
  93. GRB 090625B: Faulkes Telescope South observations
  94. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  95. GRB 090625B: a long GRB localized by INTEGRAL
  96. GRB 090625: Fermi GBM detection
  97. GRB 090618: Correction to GCN 9568
  98. GRB 090617: Suzaku WAM observation of the prompt emission
  99. GRB 090618: Suzaku WAM observation of the prompt emission
  100. GRB 090621A: Enhanced Swift-XRT position

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