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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"

32501 results found.

  1. GRB021219: Correction to GCN 1766
  2. VLT spectra of GRB 021211 revisited
  3. GRB021219: a long GRB localized by INTEGRAL
  4. GRB021211: APO optical observations
  5. IPN detection of continued activity from SGR1806-20
  6. XRF 020903 : HST observations
  7. GRB 021201: Optical Observations
  8. GRB 021211, optical observations
  9. GRB 021211: CTIO observations
  10. GRB021211: Measurement of Early Time Afterglow
  11. VLT spectrum of GRB 021211
  12. GRB 021211: early break in light curve
  13. GRB021211, BVRI field photometry
  14. GRB021211: Optical observations in CrAO
  15. GRB 021211, IR observations
  16. GRB 021211, optical observations
  17. GRB 021211: Optical Observations
  18. GRB021211: Kiso Observations
  19. GRB 021201, optical observations
  20. GRB 021211: Radio Observations
  21. GRB021211: Optical observations
  22. GRB 021201 (short/hard), NOT observations
  23. SUB-MM SEARCH FOR GRB 021211
  24. Chandra observation of the IPN error box of GRB021201 (short/hard)
  25. GRB 021211, R- and I-band observations
  26. GRB021211 - Upper limits from recent and historical observations
  27. GRB021211, OT at 108 s
  28. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  29. HETE 2493: Optical observations
  30. GRB 021125: Radio Observations
  31. IPN triangulation of GRB021206 (small error box)
  32. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  33. GRB021201, BVRcIc field photometry
  34. GRB 021201, Radio Observations
  35. GRB 021201: Optical Observations
  36. GRB 021201: BOOTES simultaneous optical observations
  37. GRB021004, late time optical observations
  38. GRB021004 Chandra Observation
  39. GRB021125 refined position
  40. IPN triangulation of GRB021125B (two large error boxes)
  41. IPN triangulation of GRB021119 (large error box)
  42. Improved IPN error box for GRB021125
  43. IPN BURST POSITION
  44. IPN confirmation of the reactivation of SGR1900+14
  45. GRB021113, SPI ACS observation
  46. GRB 021112: Afterglow or Variable Star?
  47. GRB021113: optical observations at Bisei
  48. GRB 021113: Evidence for a Dark Optical Afterglow
  49. GRB 021112: Variable Source in R-band search
  50. GRB021112: Optical Observations
  51. IPN triangulation of GRB021109 (portion of annulus)
  52. IPN triangulation of GRB021113 (=H2449; annulus)
  53. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  54. GRB 021113: Optical Observations
  55. GRB 021113: Optical Observations
  56. GRB021113 (=H2449): A Long GRB Localized by HETE
  57. GRB 021112: Optical Observations
  58. GRB 021112: R-band search
  59. IPN triangulation of GRB021108 (large error box)
  60. GRB021112 (=H2448): A Long GRB Localized by HETE
  61. GRB 021016: Optical Observations
  62. GRB021004: Near infrared spectroscopy
  63. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  64. Spectropolarimetry of GRB021004
  65. GRB021104: optical observations
  66. GRB021104: Candidate present in DSS
  67. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  68. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  69. IPN triangulation of GRB021025 (portion of annulus)
  70. IPN triangulation of GRB021027 (single large error box)
  71. GRB021004, late-time optical observations
  72. IPN triangulation of GRB021027 (two large error boxes)
  73. GRB 021023: Infrared Imaging
  74. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  75. IPN triangulation of SGR1900+14, October 22 2002
  76. GRB 021004: optical observations
  77. GRB021004: Optical Observations
  78. GRB 020813; likely host galaxy.
  79. IPN triangulation of GRB021020 (smaller error box)
  80. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  81. GRB 021008, radio observations
  82. GRB 021016, optical observations
  83. GRB 021004: VRI observations at TNG: possible break
  84. GRB021016, optical observations
  85. GRB 021008, optical observations
  86. GRB021016(=H2397): A Long GRB Localized by HETE
  87. IPN triangulation of GRB021016 (area corrected)
  88. IPN triangulation of GRB021016 (small error box)
  89. GRB021004: Optical Observations
  90. IPN triangulation of GRB021013 (single error box)
  91. GRB 021004: optical spectroscopy on Oct 11
  92. IPN triangulation of GRB021013 (two small error boxes)
  93. GRB021004: High-resolution optical spectroscopy
  94. XRF 020903: flattening of the optical light curve.
  95. GRB021004, UBVRcIc field photometry update
  96. IPN triangulation of GRB021008 (single error box)
  97. GRB021004: Optical Observations
  98. GRB 021004 submm observations
  99. IPN triangulation of GRB021008 (two small error boxes)
  100. GRB 021004: Optical/NIR Observations

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