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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"

25008 results found.

  1. GRB021211: Optical observations in CrAO
  2. GRB 021211, optical observations
  3. GRB021211: Kiso Observations
  4. GRB 021201, optical observations
  5. GRB021211: Optical observations
  6. GRB 021201 (short/hard), NOT observations
  7. SUB-MM SEARCH FOR GRB 021211
  8. Chandra observation of the IPN error box of GRB021201 (short/hard)
  9. GRB 021211, R- and I-band observations
  10. GRB021211 - Upper limits from recent and historical observations
  11. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  12. IPN triangulation of GRB021206 (small error box)
  13. IPN triangulation of GRB021205 (large error box)
  14. GRB021201, BVRcIc field photometry
  15. GRB 021201: BOOTES simultaneous optical observations
  16. IPN triangulation of GRB021201 (short/hard burst, small error box)
  17. GRB021004, late time optical observations
  18. GRB021004 Chandra Observation
  19. IPN detection of continued SGR1900+14 activity
  20. Improved IPN error box for GRB021125
  21. IPN BURST POSITION
  22. IPN triangulation of GRB021125 (INTEGRAL BURST)
  23. GRB021125 : A long GRB localized by INTEGRAL
  24. IPN confirmation of the reactivation of SGR1900+14
  25. GRB021113, SPI ACS observation
  26. GRB 021112: Afterglow or Variable Star?
  27. GRB021113: optical observations at Bisei
  28. GRB 021113: Evidence for a Dark Optical Afterglow
  29. GRB021112, BVRI field photometry
  30. GRB 021112: Variable Source in R-band search
  31. GRB021112: Optical Observations
  32. IPN triangulation of GRB021113 (=H2449; annulus)
  33. GRB 021113: Optical observations
  34. GRB 021112: RAPTOR Observations
  35. GRB021113 (=H2449): A Long GRB Localized by HETE
  36. GRB021112 (=H2448): A Long GRB Localized by HETE
  37. GRB 021016: Optical Observations
  38. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  39. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  40. SGR1900+14 activity, November 2-4, 2002
  41. GRB021104: optical observations
  42. Detection of activity from SGR 1900+14 with the RXTE/PCA
  43. IPN triangulation of GRB021027 (single large error box)
  44. IPN triangulation of GRB021027 (two large error boxes)
  45. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  46. GRB 021004: optical observations
  47. IPN triangulation of GRB021023 (small error boc)
  48. GRB 020813; likely host galaxy.
  49. IPN triangulation of GRB021020 (smaller error box)
  50. IPN triangulation of GRB021020
  51. GRB 021008, optical observations
  52. IPN triangulation of GRB021016 (small error box)
  53. IPN triangulation of GRB021014 (large error box)
  54. IPN triangulation of GRB021013 (single error box)
  55. GRB 021004: optical spectroscopy on Oct 11
  56. IPN triangulation of GRB021013 (two small error boxes)
  57. GRB021004: High-resolution optical spectroscopy
  58. XRF 020903: flattening of the optical light curve.
  59. GRB021004, UBVRcIc field photometry update
  60. IPN triangulation of GRB021008 (single error box)
  61. GRB 021004 submm observations
  62. IPN triangulation of GRB021008 (two small error boxes)
  63. GRB021004 Chandra HETG Observations
  64. GRB 021004: Optical/NIR Observations
  65. GRB 021004: Additional V-band Polarimetric Observations
  66. GRB021004: optical observation
  67. GRB 021004: Host Galaxy Star Formation Rate
  68. GRB 021004 submm observations
  69. GRB 021004: WC wind?
  70. GRB021004: NIR and Optical observations
  71. GRB 021004: Optical observations, AUDE network
  72. GRB 021004 - VLA Radio Observations
  73. GRB 021004 - Unusual Radio-to-Submm Spectrum
  74. GRB 021004: optical spectroscopy
  75. IPN triangulation of GRB021007 (annulus)
  76. GRB021004: optical observations and predicted break time
  77. GRB021004: BVRc photometry
  78. GRB021004 radio observation
  79. HETE fluences for GRB021004
  80. GRB 021004: Optical Photometry at 2.5 Days
  81. GRB 021004: polarimetric observations
  82. GRB 021004: V-band Polarimetric Observations
  83. GRB021004: Update Bisei photometric data
  84. IRAM Millimeter detection of GRB 021004
  85. GRB 021004 radio observation
  86. GRB 021004: Optical Photometry at 1.5 Days
  87. GRB021004, BVRcIc field photometry
  88. GRB021004: Optical Spectroscopy
  89. GRB 021004 radio search
  90. XRF020903, BVRI field photometry
  91. XRF020903: TNG and Asiago photometry
  92. GRB 020903: Optical observations at RIKEN
  93. XRF 020903: Correction to GCN 1560
  94. XRF 020903: VRI observations
  95. XRF 020903: R band observations
  96. XRF 020903: Archival Optical Images
  97. Radio Observations of XRF 020903: The Missing Link
  98. XRF 020903: Supernova
  99. IPN triangulation of GRB020923 (two error boxes)
  100. IPN triangulation of GRB020914B

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