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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"

26042 results found.

  1. GRB041006: Near Infrared observations
  2. GRB040924, BVRcIc field calibration
  3. GRB041006: Fading X-ray Afterglow Observed with Chandra
  4. GRB041006: VLT observations of the afterglow and host galaxy
  5. GRB041006: Optical observations and Potential host galaxy
  6. GRB041006, BVRcIc field calibration
  7. GRB 041006: SARA afterglow observations
  8. Search for SN light in XRF 040912 with MEGACAM
  9. GRB 040916: Afterglow Color at Early Times
  10. GRB 041006 Optical afterglow observations
  11. GRB 041006: BR observations with VATT
  12. GRB 041006: Redshift confirmed
  13. GRB041006: Liverpool Telescope optical observations
  14. GRB 041006: Colour measurement
  15. GRB041006: break in the light curve
  16. GRB 041006: Radio Observations
  17. GRB041006, further submilllimetre observations
  18. GRB 041006 : optical follow-up observation at Lulin Observatory
  19. GRB 041006 : Optical follow-up observation at TAROT
  20. GRB041006: Optical photometry and spectroscopy at TNG
  21. GRB041006 (= H3570): Chandra Observations In Progress
  22. GRB 041006 : optical observation at Bisei
  23. GRB041006, optical I observation
  24. GRB041006, submillimetre observations
  25. GRB 041006: Optical decay
  26. GRB041006: Fading of optical afterglow candidate
  27. GRB 041006: Finding chart
  28. GRB 041006: Optical afterglow candidate
  29. GRB 040924: Second Epoch WSRT Radio Observations
  30. radio observations, GRB 040924
  31. GRB040924,optical observation
  32. GRB040924, RTT150 optical observation
  33. GRB 040924: detection of possible host galaxy by Subaru
  34. GRB040924, RTT150 optical observation
  35. GRB040924: Afterglow magnitude at t=17.5hr
  36. GRB 040924: WSRT Radio Observations
  37. GRB 040924: Subaru NIR observation
  38. GRB040924: Optical afterglow properties
  39. GRB040924 (H3564): Optical afterglow candidate
  40. XRF 040912: Radio Observations
  41. XRF 040916: Radio Observations
  42. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  43. TAROT Observations of GRB 040916 (HETE #3558)
  44. GRB040912(=H3557): Candidate Optical Afterglow
  45. XRF040912, BVRcIc field calibration
  46. XRF040916, BVRcIc field calibration
  47. GRB040916: Archival optical observations
  48. GRB040916: Optical observations
  49. GRB 040912: Optical Observations
  50. GRB 040912, BVRI observations
  51. HETE 3557: Optical observations
  52. GRB040827: analysis of the XMM-Newton observation
  53. GRB 040827 - Radio Observations
  54. GRB040825A: Optical observations
  55. GRB040825A: Optical observations
  56. GRB 040827: optical and NIR observations at the VLT
  57. GRB 040827: UKIRT - 2nd epoch K-band imaging
  58. GRB 040827: 2nd epoch of Magellan K-band imaging
  59. GRB 040827: Detection of NIR afterglow
  60. GRB 040827: Possible detection of optical afterglow
  61. GRB040825B, BVRcIc field photometry
  62. GRB040825A, BVRcIc field photometry
  63. GRB 040825: Optical observations
  64. XRF040812: possible afterglow second Chandra observation
  65. GRB 040812: Second epoch CXO Observations
  66. XRF040812: possible afterglow
  67. GRB 040810: Optical observations of a limited region
  68. XRF040701: Second-Epoch Chandra Observations
  69. XRF040701: First-Epoch Chandra Observations
  70. GRB 030329: Rebrightening of hyperluminal ejecta.
  71. GRB040511: Retraction of redshift identification
  72. GRB 040511, very fast decay?
  73. GRB 030324: Detection and Color of Host Galaxy
  74. GRB040511: Redshift identifcation
  75. GRB 040511: Optical limit
  76. GRB040511: Candidate optical/NIR afterglow
  77. GRB040422, BVRcIc field calibration
  78. GRB040422: optical and NIR observations at the VLT
  79. GRB 040403: Optical Observations
  80. GRB 040323, a dark GRB ?
  81. GRB040223: Deep NIR NTT data re-analysis
  82. GRB 040223: XMM-Newton results
  83. GRB040223, improved XMM position
  84. GRB 031203, possible supernova
  85. MASTER: RXTE GRB040308 optical observation
  86. RXTE GRB040229 optical observation: no candidate
  87. GRB 040228 Optical observations
  88. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  89. GRB031203: Chandra Observations
  90. GRB040106: refined X-ray transient position
  91. GRB040106, likely optical afterglow
  92. GRB040106: Second Epoch Optical Observations
  93. GRB 031220: Optical observations of Chandra X-ray sources
  94. GRB031220: Palomar Observations
  95. GRB031203, improved XMM position
  96. GRB 031203: Discovery of a dust echo
  97. GRB 021203: A Normal GRB viewed far off axis?
  98. GRB 031203: Variable Radio Source
  99. GRB 031203: Optical/IR Astrometry
  100. GRB 031203: Radio detection

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