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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"

2707 results found.

  1. Optical/NIR observations of GRB001109
  2. GRB 001018, Possible Radio Afterglow
  3. HETE positions added to GCN
  4. GRB000926 - Optical observations
  5. "Snapshot" afterglow IDs and GRB 000830
  6. IPN localization of GRB000730B
  7. GRB 990510: Possible detection of a host galaxy
  8. possible optical counterpart of GRB 000630
  9. GRB990308, HST/STIS observations of the host galaxy
  10. GRB000615, further R-band photometry
  11. BeppoSAX X-ray transient/possible GRB000608
  12. GRB 000418: Detection of the Host Galaxy
  13. IPN localization and time history of GRB000528
  14. New IPN localization of GRB000529
  15. GRB000508B, optical photometry
  16. Possible GRB-related phenomenon
  17. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  18. Refined IPN error box for GRB000408
  19. GRB000408 [IPN Position]
  20. GRB000315 [IPN Positions]
  21. GRB 000301C: Optical Spectrum and Redshift
  22. GRB 000301C: Optical Spectrum and Redshift
  23. GRB 000301C: A Precise Redshift Determination
  24. IPN error box for GRB000307
  25. GRB000301C - Host galaxy not detected in R (?)
  26. GRB000301C, near-infrared observations (JHK' imaging)
  27. GRB000301C, optical observations
  28. GRB000301C, near-infrared observations (JHK' photometry)
  29. GRB 000301A, Radio Observations
  30. GRB000226 [IPN Position]
  31. IPN annulus for GRB000214
  32. Correction to Chandra Position of GRB000210 afterglow
  33. GRB000210: possible afterglow detection with BeppoSAX NFI
  34. BATSE+IPN location of GRB000131
  35. BATSE location of GRB000126
  36. IPN localization of GRB000126
  37. GRB991216 late optical observation
  38. BEPPOSAX GRBM Localization of GRB991226
  39. IPN error boxes for GRB991229
  40. IPN localization of GRB991226
  41. IPN error boxes for GRB991221
  42. IPN error box for GRB991216
  43. GRB991216 Optical and IR observations
  44. GRB 991216 Optical Observations
  45. GRB 991216, optical observations
  46. GRB991208, optical observations
  47. GRB 991106 Optical Observations
  48. GRB 991014, Optical Observations
  49. GRB990907 and 990908
  50. GRB 990806, Optical Observations
  51. GRB990806: possible X-ray afterglow, BeppoSAX
  52. GRB990705: No Evidence for Neutrino Signal
  53. BeppoSAX GRB990705: possible X-ray afterglow
  54. GRB 990704, optical observations
  55. GRB990704
  56. GRB990704
  57. GRB990704: possible X-ray afterglow
  58. Identification of a possible optical counterpart for GRB990704
  59. GRB 990510 optical observations
  60. GRB990510: NFI X-ray source
  61. GRB 990510 optical observations
  62. Refined IPN error box for GRB990506
  63. GRB 990506: Limits on the possible optical transient
  64. GRB 990506, armchair astronomy
  65. GRB 970228: Redshift and properties of the host galaxy
  66. GRB981220 VLBA observations
  67. GRB990321 REFINED IPN ANNULUS
  68. GRB990321 IPN TRIANGULATION
  69. GRB 990316 Optical Observations
  70. GRB990316: simultaneous optical observation
  71. ASM/IPN error box for GRB 990308 (BATSE #7457)
  72. GRB990308, Possible new SGR~0209+70
  73. GRB981220, IPN localization
  74. GRB 981220, radio observations
  75. GRB 990123: Updated Keck Spectroscopy Results
  76. GRB990123, Optical observation
  77. GRB 990123: New Constraints on Possible Foreground Galaxies
  78. Search for Potential Images of GRB 990123
  79. Search for Potential Images of GRB 990123
  80. GRB990123 IPN annulus
  81. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  82. GRB 990123 Spectroscopic Redshifts
  83. GRB 990123: Possible Gravitationally Lensed Burst?
  84. GRB 990123 optical observations
  85. GRB 990123: Bright New Source, Possible Optical Transient
  86. Possible identification of SN1999E with GRB980910
  87. GRB981220
  88. GRB 981226 optical observations
  89. GRB 981220
  90. GRB980703: Radio transient
  91. SGR1627-41, Refined IPN annulus location
  92. Reduced error box of SGR 1627-41
  93. SGR 1627-41
  94. SGR1900+14
  95. SGR1900+14
  96. GRB980519 optical observations
  97. GRB980519 Optical Observations
  98. GRB 980425 Brightness Temperature
  99. GRB980329 infrared observations
  100. Optical Observations of the GRB 971227 field

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