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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

28047 results found.

  1. GRB030204 field photometry
  2. GRB020819: Kiso R and I band observations
  3. GRB030131: Candidate Optical Afterglow
  4. IPN triangulation of GRB030204 (small error box)
  5. GRB 030131, optical observations
  6. GRB 030131: afterglow candidate
  7. GRB 030115, late-time optical observations
  8. GRB030131: corrected INTEGRAL position
  9. GRB 020819: Host galaxy at Radio Position
  10. IPN triangulation of GRB030131
  11. GRB 030131 optical observations
  12. GRB 030131 optical observations
  13. A long GRB detected by INTEGRAL
  14. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  15. GRB 030115, simultaneous observations by BOOTES-1
  16. GRB 030115: IR observations with IRSF/SIRIUS
  17. IPN triangulation of GRB030115C (large error box)
  18. GRB030115, afterglow candidate
  19. GRB 021211: R-band observations at late-time
  20. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  21. GRB 030115 : Possible IR counterpart
  22. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  23. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  24. GRB 030115: APO Optical Observations
  25. Information about where HETE will be pointing
  26. VLT spectroscopy of the probable host of GRB 021211
  27. IPN triangulation of GRB030101 (two large error boxes)
  28. GRB 021211: Probable Host and Underlying Supernova
  29. GRB 021112: Evidence for Another Dark Optical Afterglow
  30. GRB 021219: OSN optical observations
  31. GRB021219, optical observations
  32. GRB021219, optical observation by MASTER
  33. VLT spectra of GRB 021211 revisited
  34. GRB021219: a long GRB localized by INTEGRAL
  35. GRB021211: APO optical observations
  36. XRF 020903 : HST observations
  37. GRB 021201: Optical Observations
  38. GRB 021211: CTIO observations
  39. GRB021211, BVRI field photometry
  40. GRB021211: Optical observations in CrAO
  41. GRB 021211, optical observations
  42. GRB021211: Kiso Observations
  43. GRB 021201, optical observations
  44. GRB021211: Optical observations
  45. GRB 021201 (short/hard), NOT observations
  46. SUB-MM SEARCH FOR GRB 021211
  47. Chandra observation of the IPN error box of GRB021201 (short/hard)
  48. GRB 021211, R- and I-band observations
  49. GRB021211 - Upper limits from recent and historical observations
  50. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  51. IPN triangulation of GRB021206 (small error box)
  52. IPN triangulation of GRB021205 (large error box)
  53. GRB021201, BVRcIc field photometry
  54. GRB 021201: BOOTES simultaneous optical observations
  55. IPN triangulation of GRB021201 (short/hard burst, small error box)
  56. GRB021004, late time optical observations
  57. GRB021004 Chandra Observation
  58. IPN detection of continued SGR1900+14 activity
  59. Improved IPN error box for GRB021125
  60. IPN BURST POSITION
  61. IPN triangulation of GRB021125 (INTEGRAL BURST)
  62. GRB021125 : A long GRB localized by INTEGRAL
  63. IPN confirmation of the reactivation of SGR1900+14
  64. GRB021113, SPI ACS observation
  65. GRB 021112: Afterglow or Variable Star?
  66. GRB021113: optical observations at Bisei
  67. GRB 021113: Evidence for a Dark Optical Afterglow
  68. GRB021112, BVRI field photometry
  69. GRB 021112: Variable Source in R-band search
  70. GRB021112: Optical Observations
  71. IPN triangulation of GRB021113 (=H2449; annulus)
  72. GRB 021113: Optical observations
  73. GRB 021112: RAPTOR Observations
  74. GRB021113 (=H2449): A Long GRB Localized by HETE
  75. GRB021112 (=H2448): A Long GRB Localized by HETE
  76. GRB 021016: Optical Observations
  77. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  78. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  79. SGR1900+14 activity, November 2-4, 2002
  80. GRB021104: optical observations
  81. Detection of activity from SGR 1900+14 with the RXTE/PCA
  82. IPN triangulation of GRB021027 (single large error box)
  83. IPN triangulation of GRB021027 (two large error boxes)
  84. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  85. GRB 021004: optical observations
  86. IPN triangulation of GRB021023 (small error boc)
  87. GRB 020813; likely host galaxy.
  88. IPN triangulation of GRB021020 (smaller error box)
  89. IPN triangulation of GRB021020
  90. GRB 021008, optical observations
  91. IPN triangulation of GRB021016 (small error box)
  92. IPN triangulation of GRB021014 (large error box)
  93. IPN triangulation of GRB021013 (single error box)
  94. GRB 021004: optical spectroscopy on Oct 11
  95. IPN triangulation of GRB021013 (two small error boxes)
  96. GRB021004: High-resolution optical spectroscopy
  97. XRF 020903: flattening of the optical light curve.
  98. GRB021004, UBVRcIc field photometry update
  99. IPN triangulation of GRB021008 (single error box)
  100. GRB 021004 submm observations

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