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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"

4000 results found.

  1. GRB030329: optical observations at Tokyo Tech
  2. Further AAVSO V,B,R observations of GRB030329
  3. GRB 030329: Additional Mt. Laguna Optical Observations
  4. GRB 030329: Observations with ANDICAM
  5. GRB030329: Optical observations
  6. GRB 030329: Correction to GCN 2056
  7. GRB 030329: optical observations
  8. GRB 030328, optical photometry
  9. GRB030329: R band light curve by MASTER
  10. GRB030329 - near contemporaneous optical limits from CONCAM
  11. GRB 030329: Optical pre-Imaging
  12. GRB 030329: visual observations
  13. GRB 030329: OT B and R photometry, decline rate
  14. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  15. RXTE detection of GRB 030329 afterglow
  16. GRB 030329: Optical Afterglow Observations
  17. GRB 030328 Optical Observations
  18. GRB030328: Decay index
  19. GRB 030329: OT candidate
  20. GRB030328: optical spectroscopy at TNG
  21. GRB030328: optical photometry at the TNG
  22. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  23. IPN triangulation of GRB030326 (single small error box)
  24. GRB 030323: SARA Optical Observations
  25. IPN triangulation of GRB030325 (two small error boxes)
  26. GRB030323: V, R, I photometry
  27. GRB 030227: fading of candidate optical afterglow 'S1-A'
  28. GRB 030227, possible optical counterpart of XMM-Newton source
  29. GRB030227 - faint tentative OT candidate
  30. XMM-Newton observation of GRB030227
  31. GRB 030227: Kyoto optical observation
  32. GRB030227: refined INTEGRAL position
  33. GRB 030131: marginal optical detection
  34. Probable GRB030112 seen by SPI ACS
  35. VLT spectroscopy of the probable host of GRB 021211
  36. IPN triangulation of GRB021219
  37. IPN detection of continued activity from SGR1806-20
  38. IPN triangulation of GRB021211B (two large error boxes)
  39. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  40. IPN detection of renewed activity from SGR1806-20
  41. GRB 021201: BOOTES simultaneous optical observations
  42. GRB021004, late time optical observations
  43. IPN detection of continued SGR1900+14 activity
  44. IPN confirmation of the reactivation of SGR1900+14
  45. IPN detection of possible reactivation of SGR1900+14
  46. GRB 021113: Evidence for a Dark Optical Afterglow
  47. GRB 021112: RAPTOR Observations
  48. GRB021112 (=H2448): A Long GRB Localized by HETE
  49. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  50. SGR1900+14 activity, November 2-4, 2002
  51. Detection of activity from SGR 1900+14 with the RXTE/PCA
  52. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  53. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  54. IPN triangulation of GRB021020 (smaller error box)
  55. IPN triangulation of GRB021020
  56. GRB021016(=H2397): A Long GRB Localized by HETE
  57. IPN triangulation of GRB021013 (two small error boxes)
  58. GRB021004: BVRc photometry
  59. GRB 021004: Optical Observations
  60. IPN triangulation of GRB020914
  61. IPN detection of a burst from SGR1900+14
  62. IPN triangulation of GRB020715 (=GRB150702)
  63. IPN triangulation of GRB150702
  64. IPN triangulation of GRB020708
  65. IPN triangulation of GRB020708
  66. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  67. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  68. AXP 1E2259+586: quasi-simultaneous optical observation
  69. AXP 1E2259+586 optical observations
  70. SGR-like Bursts from the AXP 1E 2259+586
  71. GRB 020604, optical observations
  72. GRB020604, optical observations
  73. IPN triangulation of GRB020604
  74. GRB020531: Optical observations
  75. GRB020525, optical observations
  76. IPN detection of possible bursts from SGR1806-20
  77. IPN triangulation of GRB020525
  78. XRF 020427: Sudden Ionospheric Disturbance (SID)
  79. Mars Odyssey joins the IPN
  80. Short RXTE/ASM transient 020406; may be a GRB
  81. XRF/GRB 011030: Detection of the Probable Host Galaxy
  82. IPN detection and localization of Cygnus X-1 flares
  83. RXTE Observations of SGR 1900+14
  84. SGR1900+14 activity
  85. IPN/HETE Detection of Bursts from SGR1900+14
  86. IPN Upper Limits to a GRB Associated With SN2002ap
  87. IPN detection of further activity from SGR1806-20
  88. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  89. GRB010923 as seen by BeppoSAX GRBM
  90. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  91. Probable SGR or Short Duration GRB Detected by HETE
  92. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  93. GRB 010629 Optical Observations
  94. GRB010629: A Burst Localized by HETE
  95. Possible burst from SGR1806-20
  96. IPN detection of SGR1900+14
  97. X-ray precursors to the large flare from SGR 1900+14
  98. SGR 1900+14: No evidence of extended X-ray emission
  99. SGR 1900+14 : RXTE observations
  100. BeppoSAX/NFI Follow-up Observation of SGR 1900+14

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