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Observing Programs at Keck Observatory with ESI on Jan 19-20, 2015 for Prochaska + Associates

This page organizes all of the projects for ESI on Jan 19-20. Each program page should include: (i) the optimal setup for the observation; (ii) a target list with finder charts and recommended exposure times; (iii) any additional notes of interest (S/N desired, priority of targets); (iv) Worst conditions (seeing, clouds) under which observations will still be useful.

Goal

This project aims to measure hydrogen and metal line column densities in DLA host galaxies and the material in their surroundings. Starting with the QPQ quasar sample, we have identified pairs with a DLA in one sightline. We then use the other QSO in the pair to probe the CGM of the DLA-host galaxy. We would like to use measurements of the hydrogen and metal columns to constrain the ionization state, metallicity, and mass of gas in the CGM sightline. We will also compare the CGM metallicities and low-ionization metal-line kinematics to those measured in the corresponding DLA sightline.

To accomplish this, we must obtain S/N >~ 10 per pix at the wavelength of the DLA's Lya line in the CGM sightline. We are also aiming for S/N >~5 per pix for the DLA itself, and S/N ~ 10 per pix for the DLA's metal-line transitions. I have noted which QSO provides the CGM and DLA sightlines in the target table below.

More instructions on the observing procedure and on using the finding charts are given below the target table.

Finally, if the seeing is > 1.1", or if you're observing through clouds, the QSO observations are probably not going to be successful. If we don't come close to our S/N goals, the data is of limited use. In addition, it is better to obtain "complete" observations of a single pair than marginal observations of more than one pair.

Here is the current observing plan:

12 degrees twilight begins at 02:32 LST (18:56 HST), and then begins at 13:45 LST (06:09 HST) in the morning.

Setup

Please use the 0.75" slit in echelle mode, unless conditions are extremely good (< 0.7" seeing). Please obtain calibrations for both the 0.75" and 0.5" slit at the beginning of the night (just in case). All observations should be taken with 1x1 binning.

Timeline (LST)

====== Jan 19 ======

01h52m - sunset

02h00m - 02h40m: sky flats, 5 x

02h40m - 02h55m: standard star G191B2B, 600 seconds, 60 seconds acquisition

02h58m - twilight ends

02h55m - 05h10m: J0250-0256, 900 seconds acquisition, 2hrs exposure

05h10m - 06h05m: J0833+3535A, 900sec acq, 2x1200s exposure

06h05m - 10h25m: J0833+3535B, 300sec acq, 4.25hrs exposure

10h25m - 13h40m: J1236+5220, 900 seconds acquisition, 3hrs exposure

13h19m - twilight begins

13h40m - 13h51m: standard star HZ44, 600 seconds, 60 seconds acquisition

13h51m: sky flats and other calibrations, if not done yet

14h26m - sunrise

====== Jan 20 ======

01h52m - sunset

02h00m - 02h40m: sky flats, 5 x (Goodrich test will be happening, so I presume there won't really be time for these, and perhaps not for the standard either.)

02h40m - 02h55m: standard star G191B2B, 600 seconds, 60 seconds acquisition

03h02m - twilight ends

02h55m - 05h10m: Finish up J0250-0256 with ~1-2 more hrs, if done move on to J0147-0330; 900 seconds acquisition

05h10m - 06h25m: J0827+3525 (Kanekar), 900sec acq, 2x1800s exposure

06h25m - 10h25m: J0833+3535B, 600sec acq, try to finish this up

10h25m - 13h40m: Finish up J1236+5220, 900 seconds acquisition, ~3hrs exposure

13h24m - twilight begins

13h40m - 13h51m: standard star HZ44, 600 seconds, 60 seconds acquisition

13h51m: sky flats and other calibrations, if not done yet

14h26m - sunrise

Target

RA (2000)

Dec (2000)

PA [deg]

Separation ["]

i_q magnitude

Redshift

Exposure (s)

Finder

Comments

Status

Log

J0147-0330A* (low z)

01:47:08.466

-03:30:56.32

Parallactic

31.3

18.90 (DLA)

2.48, z_DLA = 2.20034

2x1200s

J0147-0330.pdf

RA Offset = 56.6, Dec Offset = 39.2

J0147-0330B* (low z)

01:47:08.466

-03:30:56.32

Parallactic

31.3

21.22 (CGM)

2.48, z_DLA = 2.20034

5.0hrs

J0147-0330.pdf

RA Offset = 35.1, Dec Offset = 61.9

J0250-0256

02:50:52.352

-02:56:16.26

21.0

9.6

20.37 (CGM), 19.39 (DLA)

2.84, 2.82, z_DLA = 2.579

3.2hrs

J0250_chart.pdf

RA Offset = -50.6, Dec Offset = -20.0

J0754+2754

J0827+3525 (Kanekar)

08:27:38.606

+35:25:05.170

Parallactic

N/A

1.0hrs

J0831+4247A*

08:31:13.773

+42:48:04.47

Parallactic

34.4

18.85 (DLA)

3.33, z_DLA = 2.561

2x1200s

J0831_chart.pdf

RA Offset = 52.1, Dec Offset = -35.6

J0831+4247B*

08:31:13.773

+42:48:04.47

Parallactic

34.4

21.15 (CGM)

3.01, z_DLA = 2.561

5.0hrs

J0831_chart.pdf

RA Offset = 85.9, Dec Offset = -42.2

J0833+3535A* (low z)

08:32:59.351

+35:36:18.84

Parallactic

28.5

18.83 (DLA)

2.34, z_DLA = 2.198

2x1200s

J0833_chart.pdf

RA Offset = 48.5, Dec Offset = -18.9

J0833+3535B* (low z)

08:32:59.351

+35:36:18.84

Parallactic

28.5

20.96 (CGM)

2.34, z_DLA = 2.198)

9.6hrs

J0833_chart.pdf

RA Offset = 37.5, Dec Offset = 7.4

J0957+6223

J1045+4351 (low z)

J1149+4300

11:50:03.498

+43:00:14.97

19.2

7.5

21.25 (CGM), 18.83 (DLA)

3.27, 3.27, z_DLA = 2.7877

at least 5.0hrs

J1149+4300_chart.pdf

RA Offset = -56.1, Dec Offset = 29.9

J1153+3530

11:53:02.212

+35:31:05.30

55.9

9.1

20.42 (DLA), 20.19 (CGM)

3.05, 2.43, z_DLA = 2.001

3.5hrs

J1153_chart.pdf

RA Offset = -0.0, Dec Offset = -59.7

J1236+5220

12:36:29.332

+52:20:57.45

-55.5

3.1

20.74 (CGM), 20.45 (DLA)

2.58, 2.57, z_DLA = 2.397

6.4hrs

J1236_chart.pdf

RA Offset = 54.5, Dec Offset = 0.8

* This pair has a separation >20", and so must be observed one at a time.

Finding Charts for QSO Pair Targets (J0250, J0831, J0833, J1153, J1236, etc)

In these charts, the two QSOs are indicated with blue (b/g QSO) and red (f/g QSO) arrows, and the offset star is indicated with a red box. The coordinates at the top (in black) are of the offset star, not the QSOs. The offset star coordinates are also listed in the star list and in the target table above (rather than the coordinates of either QSO). alpha_pos gives the position angle of the pair; this information is also in the star list so that the slit gets set at this angle automatically, but please double check. delta theta gives the separation between the QSOs in arcseconds. The black delta RA and delta Dec (with bars over them) give the offset from the star to the midpoint between the QSOs. These offsets are also included in the star list. A positive RA offset moves the telescope East, and a positive Dec offset moves the telescope North.

The offsets printed in blue and red show how to move from the offset star to the b/g and f/g QSO, respectively. This info should not be needed, however.

Main Pages

Esi2015Jan (last edited 2015-01-18 01:38:46 by KateRubin)