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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"

19424 results found.

  1. GRB020819: Kiso R and I band observations
  2. GRB030131: Candidate Optical Afterglow
  3. GRB 030131, optical observations
  4. GRB 030131: afterglow candidate
  5. GRB 030115, late-time optical observations
  6. GRB030131: corrected INTEGRAL position
  7. GRB 020819: Host galaxy at Radio Position
  8. IPN triangulation of GRB030131
  9. GRB 030131 optical observations
  10. GRB030131: refined position
  11. GRB 030131 optical observations
  12. A long GRB detected by INTEGRAL
  13. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  14. GRB 030115, simultaneous observations by BOOTES-1
  15. GRB 030115: IR observations with IRSF/SIRIUS
  16. GRB030115, afterglow candidate
  17. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  18. GRB 030115 : Possible IR counterpart
  19. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  20. GRB 030115: APO Optical Observations
  21. IPN triangulation of GRB030102 (annulus)
  22. VLT spectroscopy of the probable host of GRB 021211
  23. GRB 021211: Probable Host and Underlying Supernova
  24. GRB 021112: Evidence for Another Dark Optical Afterglow
  25. GRB 021219: OSN optical observations
  26. GRB021219, optical observations
  27. GRB021219, optical observation by MASTER
  28. GRB021219: a long GRB localized by INTEGRAL
  29. GRB021211: APO optical observations
  30. IPN detection of continued activity from SGR1806-20
  31. XRF 020903 : HST observations
  32. GRB 021201: Optical Observations
  33. GRB 021211: CTIO observations
  34. GRB 021211: early break in light curve
  35. GRB021211, BVRI field photometry
  36. GRB021211: Optical observations in CrAO
  37. GRB 021211, optical observations
  38. GRB021211: Kiso Observations
  39. GRB 021201, optical observations
  40. GRB021211: Optical observations
  41. GRB 021201 (short/hard), NOT observations
  42. Chandra observation of the IPN error box of GRB021201 (short/hard)
  43. GRB 021211, R- and I-band observations
  44. GRB021211 - Upper limits from recent and historical observations
  45. GRB 021204: I-band Observations
  46. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  47. GRB 021125: Radio Observations
  48. IPN detection of renewed activity from SGR1806-20
  49. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  50. GRB021201, BVRcIc field photometry
  51. GRB 021201: BOOTES simultaneous optical observations
  52. GRB021004, late time optical observations
  53. GRB021125 : A long GRB localized by INTEGRAL
  54. GRB 021112: Afterglow or Variable Star?
  55. GRB021113: optical observations at Bisei
  56. GRB 021113: Evidence for a Dark Optical Afterglow
  57. GRB021112, BVRI field photometry
  58. GRB 021112: Variable Source in R-band search
  59. GRB021112: Optical Observations
  60. GRB 021113: Optical observations
  61. GRB 021112: RAPTOR Observations
  62. GRB021113 (=H2449): A Long GRB Localized by HETE
  63. GRB 021016: Optical Observations
  64. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  65. SGR1900+14 activity, November 2-4, 2002
  66. GRB021104: optical observations
  67. Detection of activity from SGR 1900+14 with the RXTE/PCA
  68. GRB 021004: optical observations
  69. GRB 021008, radio observations
  70. GRB 021008, optical observations
  71. IPN triangulation of GRB021014 (large error box)
  72. IPN triangulation of GRB021013 (two small error boxes)
  73. XRF 020903: flattening of the optical light curve.
  74. GRB021004, UBVRcIc field photometry update
  75. IPN triangulation of GRB021008 (two small error boxes)
  76. GRB021004 Chandra HETG Observations
  77. GRB 021004: Optical/NIR Observations
  78. GRB 021004: Additional V-band Polarimetric Observations
  79. GRB021004: optical observation
  80. GRB 021004: Host Galaxy Star Formation Rate
  81. GRB 021004: WC wind?
  82. IPN triangulation of GRB021008
  83. GRB 021004: Optical observations, AUDE network
  84. IPN triangulation of GRB021007 (annulus)
  85. GRB021004: BVRc photometry
  86. GRB021004 radio observation
  87. GRB 021004 continued IR fading
  88. GRB 021004: Optical Photometry at 2.5 Days
  89. GRB 021004: polarimetric observations
  90. GRB 021004: V-band Polarimetric Observations
  91. GRB021004: Update Bisei photometric data
  92. GRB 021004 radio observation
  93. GRB 021004: Optical Observations
  94. GRB021004: continued fading
  95. GRB 021004: Optical Photometry at 1.5 Days
  96. GRB021004, Optical Observations
  97. GRB021004, BVRcIc field photometry
  98. GRB021004: Optical Spectroscopy
  99. GRB 021004: Optical Observations
  100. GRB 021004, SPM optical observations

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