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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"

26040 results found.

  1. GRB000620, Radio Observations
  2. GRB981226, HST/STIS observations of the host galaxy
  3. GRB000630, optical observations
  4. GRB 000630: Detection of the Optical Afterglow
  5. GRB000630, BVRI Field Photometry
  6. GRB 990506, HST/STIS Observations of the Host Galaxy
  7. GRB990308, HST/STIS observations of the host galaxy
  8. GRB990123, HST/STIS observations of the host galaxy
  9. GRB000615, further R-band photometry
  10. GRB000528: follow-up X-ray measurements and update of IPN annulus
  11. Optical Follow-up of GRB000529 Error Box
  12. X-ray Afterglow of GRB 000529
  13. GRB000519, BVRI field photometry
  14. GRB 000418, Optical observation
  15. GRB000508B, BVR field photometry
  16. Possible GRB-related phenomenon
  17. GRB000424, UBVRI field photometry
  18. GRB 000429, UBVRI field photometry
  19. GRB000418, K'-band photometry
  20. GRB 000418, Optical Observation
  21. GRB 000418, optical observation
  22. GRB 000418, Optical Observation
  23. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  24. Budget cuts in BeppoSAX operations: impact on GRB observations
  25. GRB000408: Optical CCD Observations from MIRO
  26. GRB000326 Optical Observations
  27. GRB 000313 - optical transient in the BATSE error box
  28. GRB 000301C: K' Observations
  29. GRB 000301c near-IR observations
  30. GRB 000301C, Optical Color
  31. GRB000301C 250 GHz detection
  32. GRB000301C, near-infrared observations (JHK' photometry)
  33. GRB000301C, optical observations
  34. GRB000301c, near-infrared observations
  35. GRB 000214 near-IR observations
  36. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  37. GRB000210, Radio Observations
  38. GRB000210 X-ray afterglow
  39. GRB000214: X-ray afterglow candidate
  40. Correction to Chandra Position of GRB000210 afterglow
  41. Chandra Observations of GRB000210 X-ray Afterglow
  42. GRB000210: possible afterglow detection with BeppoSAX NFI
  43. GRB 991208, radio observations
  44. GRB 000115 Optical observations
  45. BATSE Observations of GRB000115
  46. Second RXTE Observation of GRB 000115
  47. GRB991216 late optical observation
  48. GRB 991216 VLBA Observations
  49. GRB 991216: J band spectrophotometry
  50. GRB 991216 RXTE ASM Observations
  51. Chandra observation of the X-ray afterglow of GRB991216
  52. GRB991216 Optical and IR observations
  53. GRB991216 radio observations
  54. GRB991216 Optical and infrared observations of Beethoven Burst
  55. GRB 991216 Radio Observations
  56. GRB 991208 Infrared Detection
  57. GRB 991216--Summary of RXTE Observations
  58. GRB 991216, Optical Afterglow
  59. GRB991216 Optical Observations
  60. R-band Observations of GRB991208 at TNG
  61. GRB 991208 Keck Spectroscopy
  62. GRB991208 - millimeter detection
  63. GRB 991208, Optical Observation
  64. GRB991208, optical observations
  65. GRB 991208 - OVRO detection
  66. GRB 991208 Optical Decay
  67. GRB 991208 optical observations
  68. GRB 991208 optical observations
  69. GRB 991208: Radio Observations
  70. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  71. GRB 991014 - BeppoSAX NFI observations
  72. GRB 991014, Optical Observations
  73. GRB 990915 optical observations
  74. GRB990907: BeppoSAX follow up and X-ray afterglow
  75. GRB 990712 Late Optical Decay and Host Galaxy
  76. GRB 990712, Optical Observation
  77. GRB990806 BeppoSAX follow up
  78. GRB990806: possible X-ray afterglow, BeppoSAX
  79. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  80. GRB 990705, radio observations
  81. GRB990704: SAX-NFI results summary
  82. BeppoSAX GRB990705: possible X-ray afterglow
  83. GRB990704: possible X-ray afterglow
  84. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  85. GRB 990627, radio observations
  86. GRB 990506 Radio Transient
  87. Late Afterglows of GRBs 990510, 990123
  88. GRB990510: X-ray afterglow
  89. GRB 990510: Broad Band Break
  90. GRB990510: NFI X-ray source
  91. GRB 990506: BATSE Observations
  92. IPN localization for GRB990506
  93. GRB981220 VLBA observations
  94. GRB990316: simultaneous optical observation
  95. GRB 981220, radio observations
  96. GRB990123, Optical Observation
  97. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  98. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  99. GRB 990123: Continued Radio Observations
  100. GRB990123, Preliminary Lens Search Results

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