Swift Observations of GRB 170214A

A.P. Beardmore (U. Leicester) and A.A. Breeveld (UCL-MSSL) for the Swift team

1. Introduction

Mailyan and Meegan (GCN Circ. 20675) reported the GRB detection. At 15:34:26.92 UT on 14 February 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170214A (trigger 508779271 / 170214649). Table 1 contains the best reported positions from Swift.

Malesani et al. (GCN Circ. 20683) reported the position from NOT for the optical afterglow of this GRB. Kruehler et al. (GCN Circ. 20686) determined a redshift of 2.53 from VLT. Table 2 is a summary of GCN Circulars about this GRB from observatories other than Swift.

2. BAT Observations and Analysis

BAT did not observe this burst.

3. XRT Observations and Analysis

XRT refined results are not available.

4. UVOT Observations and Analysis

The Swift/UVOT began settled observations (Breeveld and Beardmore GCN Circ. 20682) of the field of GRB 170214A 38603 s after the LAT trigger (Mailyan and Meegan, GCN Circ. 20675). No optical afterglow consistent with the XRT’s source 1 position (Beardmore et al., GCN Circ. 20679, Troja et al., GCN Circ. 20681) is detected in the initial UVOT exposures. Table 3 gives preliminary magnitudes using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc., 1358, 373). No correction has been made for the expected extinction in the Milky Way corresponding to a reddening of E_B-V of 0.36 mag. in the direction of the GRB (Schlegel et al. 1998).

Figure 1. The BAT light curve is not available.

RA (J2000) Dec (J2000) Error Note Reference

17^h05^m21.95^s -01°53'14.9" 2.4" XRT Beardmore et al. GCN Circ. 20691

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes

Optical Troja et al. 20681 RATIR Optical and NIR Observations RATIR detection

Optical Malesani et al. 20683 NOT optical afterglow confirmation NOT detection

Optical Schady and Kruehler 20684 GROND detection in all bands GROND detection

Optical Troja et al. 20685 RATIR Optical and NIR Afterglow
Confirmation RATIR detection

Optical Kruehler et al. 20686 VLT/X-shooter spectroscopy and
tentative redshift VLT spectroscopy

Optical Mazaeva et al. 20687 Mondy optical upper limit Mondy upper limits

Gamma-ray Mailyan and Meegan 20675 Fermi GBM detection Fermi GBM E_peak=408.50±9.09 keV
T₉₀=123 seconds
Fluence=1.8±0.002x10^-4erg cm^-2
(99.2 percentile for long GRBs)

Gamma-ray Racusin et al. 20676 Fermi-LAT detection Fermi LAT E_max=7.8 GeV

Gamma-ray Frederiks et al. 20678 Konus-Wind observation Konus-Wind E_peak=330 (-19,+21) keV

Table 2. Summary of GCN Circulars from other observatories sorted by band and then circular number.

Filter T_start(s) T_stop(s) Exp(s) Mag

w1 38603 65287 4856 >21.0

RA (J2000)	Dec (J2000)	Error	Note	Reference
17^h05^m21.95^s	-01°53'14.9"	2.4"	XRT	Beardmore et al. GCN Circ. 20691

Band	Authors	GCN Circ.	Subject	Observatory	Notes
Optical	Troja et al.	20681	RATIR Optical and NIR Observations	RATIR	detection
Optical	Malesani et al.	20683	NOT optical afterglow confirmation	NOT	detection
Optical	Schady and Kruehler	20684	GROND detection in all bands	GROND	detection
Optical	Troja et al.	20685	RATIR Optical and NIR Afterglow Confirmation	RATIR	detection
Optical	Kruehler et al.	20686	VLT/X-shooter spectroscopy and tentative redshift	VLT	spectroscopy
Optical	Mazaeva et al.	20687	Mondy optical upper limit	Mondy	upper limits
Gamma-ray	Mailyan and Meegan	20675	Fermi GBM detection	Fermi GBM	E_peak=408.50±9.09 keV T₉₀=123 seconds Fluence=1.8±0.002x10^-4erg cm^-2 (99.2 percentile for long GRBs)
Gamma-ray	Racusin et al.	20676	Fermi-LAT detection	Fermi LAT	E_max=7.8 GeV
Gamma-ray	Frederiks et al.	20678	Konus-Wind observation	Konus-Wind	E_peak=330 (-19,+21) keV

Filter	T_start(s)	T_stop(s)	Exp(s)	Mag
w1	38603	65287	4856	>21.0

Table 3. UVOT observation reported by Breeveld and Beardmore (GCN Circ. 20682). The start and stop time of the exposure are given in seconds since the BAT trigger. The preliminary 3-σ upper limit is given. No correction has been made for extinction in the Milky Way.

February 18, 2017