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instruments [2022/03/11 00:11] – created holtzinstruments [2026/01/30 05:52] (current) – external edit 127.0.0.1
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-= Instrument upgrades / New instruments =+===== Instrument upgrades / New instruments =====
  
-== [=#apogeefeed] Fiber feed from 3.5m to SDSS/APOGEE ==+====  Fiber feed from 3.5m to SDSS/APOGEE ====
  
-== White Paper: '''"NETWORKED ASTRONOMY AT APACHE POINT OBSERVATORY"''' ==+=== White Paper: NETWORKED ASTRONOMY AT APACHE POINT OBSERVATORY ===
  
-'''ABSTRACT'''+**ABSTRACT**
  
 We propose to initiate a project to implement a fiber optic network at Apache Point Observatory We propose to initiate a project to implement a fiber optic network at Apache Point Observatory
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 plane of the NMSU 1 m telescope where they will replace and improve the existing fiber run. plane of the NMSU 1 m telescope where they will replace and improve the existing fiber run.
  
-The full paper can be downloaded here.+The full paper can be downloaded {{:wiki:inst:apofiber.2.pdf|here}}
  
-http://astronomy.nmsu.edu:8000/apo-wiki/attachment/wiki/Instruments/APOfiber.2.pdf +== Assumed Parameters for APOGEE == 
- +  * R=22,500 from 1.51 - 1.70 um,  300 2" dia fibers in SDSS 2.5m f/5 focal plane 
-''' +  * ~15% throughput --> S/N = 100/pix for H > 12.2 in t = 3 hrs 
-Assumed Parameters for APOGEE:''' +  * radial velocity to 100 m/sec
- +
-* R=22,500 from 1.51 - 1.70 um,  300 2" dia fibers in SDSS 2.5m f/5 focal plane +
- +
-* ~15% throughput --> S/N = 100/pix for H > 12.2 in t = 3 hrs +
- +
-* radial velocity to 100 m/sec+
  
 === Possible 3.5m Feed Configurations === === Possible 3.5m Feed Configurations ===
  
-* Single fiber: 0.7" at F/10, 1.4" at f/5 (i.e., with focal reduction) +  * Single fiber: 0.7" at F/10, 1.4" at f/5 (i.e., with focal reduction) 
- +  * IFU 1.4" spaxels, 217 elements, ~39" across, lenslet array in front for ~100% fill factor and f/5 conversion 
-* IFU 1.4" spaxels, 217 elements, ~39" across, lenslet array in front for ~100% fill factor and f/5 conversion +  * MOS ~ 200-300 1.4" fibers (with lenslets) in 8' FOV (pretty tightly packed!) or ~30 Randomly targeted objects (e.g in 7-fiber bundles) in 8' FOV.
- +
-* MOS ~ 200-300 1.4" fibers (with lenslets) in 8' FOV (pretty tightly packed!) or ~30 Randomly targeted objects (e.g in 7-fiber bundles) in 8' FOV.+
  
 === Science Cases Overview === === Science Cases Overview ===
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 John Bally, Kevin Bundy, Jon Holtzman, Don York, Jennifer Sobeck John Bally, Kevin Bundy, Jon Holtzman, Don York, Jennifer Sobeck
  
-'''APOGEE Dense Pack IFU'''+== APOGEE Dense Pack IFU ==
  
-* Nearby Galactic Star and star clusters [Bally ~ See attached]+  * Nearby Galactic Star and star clusters [Bally ~ See attached] 
 +  * Nearby HII regions and post-main-sequence objects [Bally ~ See attached] 
 +  * Young Massive Clusters (YMCs) and Super Star Clusters (SSCs) [Bally ~ see attached] 
 +  * Massive Stellar Transient Nearby Galaxies [Bally ~ See attached] 
 +  * Individual abundances in globular cluster stars from near-IR, perhaps from an IFU [Holtzman] 
 +  * Integrated light of globular clusters 
 +  * Dwarf spheroidals [Holtzman, Sobeck] 
 +  * Dwarf galaxies [Bundy, Holtzman] 
 +  * Extragalactic (Emission lines, Stellar populations, and Stellar Dynamics) [Bundy ~ See below]
  
-* Nearby HII regions and post-main-sequence objects [Bally ~ See attached]+== Single object science ==
  
-* Young Massive Clusters (YMCs) and Super Star Clusters (SSCs) [Bally ~ see attached]+  * Abundances of Hipparcos sub-giants [Holtzman] 
 +  * Radial velocity monitoring of late-type stars  
 +  * supernova followup in H band 
 +  * Survey of B[e] stars [Chojnowski]
  
-* Massive Stellar Transient Nearby Galaxies [Bally ~ See attached]+== APOGEE MOS ==
  
-* Individual abundances in globular cluster stars from near-IR, perhaps from an IFU [Holtzman]+  * The nature of star and clusters in the Central Molecular Zone (CMZ) and nearby starburst galaxies [Bally ~ See attached] 
 +  * Blind Emission-Line Searches of Deep Extra-Galactic Fields [Bally ~ See attached]
  
-* Integrated light of globular clusters+== Future Fiber Feeds ==
  
-* Dwarf spheroidals [Holtzman, Sobeck]+  * A Visual-Wave fiber bundle for the APO 3.5 meter [Bally ~ See attached] 
 +  * Visual wave band IFU observations of nebula [York ~ See below]
  
-* Dwarf galaxies [Bundy, Holtzman] +== Detailed Science Cases ==
- +
-* Extragalactic (Emission lines, Stellar populations, and Stellar Dynamics) [Bundy ~ See below] +
- +
-''' Single object science ''' +
- +
-* Abundances of Hipparcos sub-giants [Holtzman] +
- +
-* Radial velocity monitoring of late-type stars  +
- +
-* supernova followup in H band +
- +
-* Survey of B[e] stars [Chojnowski] +
- +
-'''APOGEE MOS''' +
- +
-* The nature of star and clusters in the Central Molecular Zone (CMZ) and nearby starburst galaxies [Bally ~ See attached] +
- +
-* Blind Emission-Line Searches of Deep Extra-Galactic Fields [Bally ~ See attached] +
- +
-'''Future Fiber Feeds''' +
- +
-* A Visual-Wave fiber bundle for the APO 3.5 meter [Bally ~ See attached] +
- +
-* Visual wave band IFU observations of nebula [York ~ See below] +
- +
-=== Detailed Science Cases ===+
  
 A number of science cases have been put forward by John Bally in an attached document ''"Science Case for a~300 fiber connection from the APO 3.5m to the SDSS spectrograph"'' for details please see the attachments of this page. A number of science cases have been put forward by John Bally in an attached document ''"Science Case for a~300 fiber connection from the APO 3.5m to the SDSS spectrograph"'' for details please see the attachments of this page.
  
-[[BR]] +== Single object possibilities ==
- +
-==== Single object possibilities ====+
  
 A single-object 3.5m feed is desirable for objects that are sufficiently spaced in the sky such that observing with the 2.5m does not offer benefits from wide field and for specific single objects of interest. The 3.5m would also potentially allow observations of fainter objects than can be done with the 2.5m. Note that the throughput gain comes from telescope area (3.5/2.5)^2^ = 1.96  (0.73 mag fainter) and also from the fact that the corrector at the 2.5m is estimated to absorb ~30% of the light in the H band (another 0.3 mag). On the other hand, there might be some additional light losses from a longer fiber run, especially if it were to involve multiple connectors. Also to avoid seeing losses that would be larger with the 1.4" fibers even at F/5 from the 3.5m, one would want to consider a lenslet array in from of a fiber bundle, such that light was collected over multiple fibers without any loss between fibers. This might lead to additional throughput gains. But ballpark, a 3.5m feed would allow observations 1 mag fainter than at the 2.5m in the same time, e.g. S/N=100/pixel at H=13.2 in 3 hours, or S/N=100/pixel at H=11 in 1 hour.  A single-object 3.5m feed is desirable for objects that are sufficiently spaced in the sky such that observing with the 2.5m does not offer benefits from wide field and for specific single objects of interest. The 3.5m would also potentially allow observations of fainter objects than can be done with the 2.5m. Note that the throughput gain comes from telescope area (3.5/2.5)^2^ = 1.96  (0.73 mag fainter) and also from the fact that the corrector at the 2.5m is estimated to absorb ~30% of the light in the H band (another 0.3 mag). On the other hand, there might be some additional light losses from a longer fiber run, especially if it were to involve multiple connectors. Also to avoid seeing losses that would be larger with the 1.4" fibers even at F/5 from the 3.5m, one would want to consider a lenslet array in from of a fiber bundle, such that light was collected over multiple fibers without any loss between fibers. This might lead to additional throughput gains. But ballpark, a 3.5m feed would allow observations 1 mag fainter than at the 2.5m in the same time, e.g. S/N=100/pixel at H=13.2 in 3 hours, or S/N=100/pixel at H=11 in 1 hour. 
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 Another application might be a survey of B[e] stars, which are B-type emission line stars that differ from classical Be stars due to the presence of forbidden emission lines and strong IR excesses. These features are attributed to a circumstellar dust component not present in the case of classical Be stars. The ~100 or so known B[e] stars are a heterogeneous group often found to be supergiants (sgB[e]), pre-main sequence (HAeB[e]), or compact planetary nebulae (cPNB[e]). However, the fact that ~50% of them remain unclassified (unclB[e]) is a testament to the complexity and richness of the emission line spectra, and also to the difficulty of conducting a uniform survey given the isolated nature of the stars. On average, B[e] stars are almost 4 magnitudes brighter in the H-band than in V-band, making them ideal targets for NIR spectroscopy. For more information, see [http://adsabs.harvard.edu/abs/1998A%26A...340..117L Lamers et al. 1998], and Miroshnichenko et al. 2007 [http://adsabs.harvard.edu/abs/2007ApJ...667..497M A] + [http://adsabs.harvard.edu/abs/2007ApJ...671..828M B]. Another application might be a survey of B[e] stars, which are B-type emission line stars that differ from classical Be stars due to the presence of forbidden emission lines and strong IR excesses. These features are attributed to a circumstellar dust component not present in the case of classical Be stars. The ~100 or so known B[e] stars are a heterogeneous group often found to be supergiants (sgB[e]), pre-main sequence (HAeB[e]), or compact planetary nebulae (cPNB[e]). However, the fact that ~50% of them remain unclassified (unclB[e]) is a testament to the complexity and richness of the emission line spectra, and also to the difficulty of conducting a uniform survey given the isolated nature of the stars. On average, B[e] stars are almost 4 magnitudes brighter in the H-band than in V-band, making them ideal targets for NIR spectroscopy. For more information, see [http://adsabs.harvard.edu/abs/1998A%26A...340..117L Lamers et al. 1998], and Miroshnichenko et al. 2007 [http://adsabs.harvard.edu/abs/2007ApJ...667..497M A] + [http://adsabs.harvard.edu/abs/2007ApJ...671..828M B].
  
-==== Extragalactic ====+== Extragalactic ==
  
-''Prepared by Kevin Bundy''+//Prepared by Kevin Bundy//
  
 Summary: Summary:
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 Scaling S/N arguments, background limited: Scaling S/N arguments, background limited:
-  1. Start with S/N = 140/pix for H > 12.2 (Vega, from 2MASS) in t = 3 hrs (on the 2.5m) +  - Start with S/N = 140/pix for H > 12.2 (Vega, from 2MASS) in t = 3 hrs (on the 2.5m) 
-  2. Larger 3.5m mirror (just D3.5/D2.5): S/N=100 at H=12.6  (muH = 13.8) +  - Larger 3.5m mirror (just D3.5/D2.5): S/N=100 at H=12.6  (muH = 13.8) 
-  3. Reduce S/N to 20: ΔH=2.1  (H=14.7)         Reduce S/N to 10: ΔH=2.9 +  - Reduce S/N to 20: ΔH=2.1  (H=14.7)         Reduce S/N to 10: ΔH=2.9 
-  4. Smooth in wavelength by a factor of 10 (Resolution now ~2000).  Goes as sqrt(smoothing): ΔH=1.25  (H=16, muH = 17.2) +  - Smooth in wavelength by a factor of 10 (Resolution now ~2000).  Goes as sqrt(smoothing): ΔH=1.25  (H=16, muH = 17.2) 
-  5. Gains from less moon illumination (dark time), no MW background:  ?? +  - Gains from less moon illumination (dark time), no MW background:  ?? 
-  6. Move to J-Band? +  - Move to J-Band? 
-  7. Large (much larger?) fiber apertures: ?+  - Large (much larger?) fiber apertures: ?
  
-[[BR]]+== More about APOGEE applicability for extragalactic studies ==
  
-==== More about APOGEE applicability for extragalactic studies ==== +//Prepared by Dmitry Bizyaev//
- +
-''Prepared by Dmitry Bizyaev''+
  
 Absorption spectra: Absorption spectra:
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 We dedicated a few APOGEE fibers in order to investigate what we can get for extragalactic studies in the frames of an APOGEE ancillary program in 2011. We have observed centers of M31, M32, and M110 in single APOGEE fibers (2" diameter) with the 2.5m telescope. Below is a table of the signal-to-noise obtained with one "visit" (67 min exposure time, typically with a plenty of Moon light). In addition to the center-of-galaxy exposures, a few fibers were allocated at "SDSS plate collision distance" (typically 80 arcsec) from the center of M32 along the minor and major axes. Figures below show combined spectra of the centers of M31 and M32, unbinned in the spectral direction, some 10 visit combined. The most prominent lines are Fe, Mg, Si, Al, and some molecular bands (CO). We dedicated a few APOGEE fibers in order to investigate what we can get for extragalactic studies in the frames of an APOGEE ancillary program in 2011. We have observed centers of M31, M32, and M110 in single APOGEE fibers (2" diameter) with the 2.5m telescope. Below is a table of the signal-to-noise obtained with one "visit" (67 min exposure time, typically with a plenty of Moon light). In addition to the center-of-galaxy exposures, a few fibers were allocated at "SDSS plate collision distance" (typically 80 arcsec) from the center of M32 along the minor and major axes. Figures below show combined spectra of the centers of M31 and M32, unbinned in the spectral direction, some 10 visit combined. The most prominent lines are Fe, Mg, Si, Al, and some molecular bands (CO).
  
-[[Image(m31_2.png)]] +{{inst:m31.png}} 
-[[Image(m32_2.png)]]+ 
 +{{inst:m32_2.png}}
  
-{{{ 
 Table: Signal-to-noise per pixel from extragalactic objects with APOGEE on 2.5m  Table: Signal-to-noise per pixel from extragalactic objects with APOGEE on 2.5m 
- +||Object    |SB(H),mag/sqarcsec | SNR/pix, 1 visit (67 min)|| 
-Object     SB(H),mag/"**2  SNR/pix, 1 visit (67 min) +||M32 center   |11.42    |     350|| 
-M32 center   11.42         350 +||M31 center   |11.76    |     178|| 
-M31 center   11.76         178 +||M110 center  |15.12     |      7|| 
-M110 center  15.12           7 +||Off-center |SB(H),mag/"**2 | SNR/pix,7 combined visits|| 
- +||M32     |    ~18.2      |      4||
- +
-Off-center SB(H),mag/"**2  SNR/pix,7 combined visits +
-M32         ~18.2            4 +
-}}}+
  
 The central surface brightness in the H-band is taken from the 2MASS Atlas of Large Galaxies. The central surface brightness in the H-band is taken from the 2MASS Atlas of Large Galaxies.
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 Given enough signal in IFU fibers for kinematics and absorption spectra abundance Given enough signal in IFU fibers for kinematics and absorption spectra abundance
 analysis, the 1.5 arcsec fiber has size analysis, the 1.5 arcsec fiber has size
-{{{+
 Distance  1.5" size Distance  1.5" size
 D=10 Mpc  0.07 kpc D=10 Mpc  0.07 kpc
 D=30 Mpc  0.22 kpc D=30 Mpc  0.22 kpc
-}}}+
  
 Conclusion 1: APOGEE+3.5m NIR IFU should be able to study kinematics and abundances of Conclusion 1: APOGEE+3.5m NIR IFU should be able to study kinematics and abundances of
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 range (1.5-1.7 microns). Bright hydrogen emission lines can be seen in  range (1.5-1.7 microns). Bright hydrogen emission lines can be seen in 
 redshifted galaxies (see "z" range and corresponding 1.5" size in the table below): redshifted galaxies (see "z" range and corresponding 1.5" size in the table below):
-{{{ 
-Line     A   z_min  z_max 1.5" size,kpc 
  
-Paschen +||Line  |   A |  z_min | z_max |1.5" |size,kpc|| 
- beta  12820  0.18  0.31  5.7  9.7 +||Paschen 
- gamma 10940  0.38  0.54 12.0 16.7 +||beta  |12820  |0.18  |0.31  |5.7 | 9.7|| 
- delta 10050  0.51  0.67 15.8 20.9+||gamma |10940  |0.38  |0.54 |12.0 |16.7|| 
 +||delta |10050  |0.51 | 0.67 |15.8 |20.9||
   ...   ...
  
 Brackett Brackett
  break 14580  0.04  0.15  1.2  4.7  break 14580  0.04  0.15  1.2  4.7
-}}}+
  
 Some higher level Brackett lines fall into the APOGEE range, and can be seen in the absorption Some higher level Brackett lines fall into the APOGEE range, and can be seen in the absorption
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 using only a few spaxels out of 300. using only a few spaxels out of 300.
  
-[[BR]] +== Optical IFU for Nebula Work ==
- +
- +
-==== Optical IFU for Nebula Work ====+
  
-''Prepared by Don York''+//Prepared by Don York//
  
 There are some applications of an IFU for projects on gas that require a feed to a high resolution spectrograph R>8000. The bundle(s) would be fed from the 2.5 meter to a 3.5m spectrograph. I list two science cases and do not consider technical challenges. There are some applications of an IFU for projects on gas that require a feed to a high resolution spectrograph R>8000. The bundle(s) would be fed from the 2.5 meter to a 3.5m spectrograph. I list two science cases and do not consider technical challenges.
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 ||Bare Bones (30 fibers to Echelle focal Plane)||$276,650||$75,170|| ||Bare Bones (30 fibers to Echelle focal Plane)||$276,650||$75,170||
  
-'''Elimination of the ARC-SAT Run'''+**Elimination of the ARC-SAT Run**
  
-Almost $18k was allotted in the budget to run 15 fibers to the dome of the ARC-SAT telescope.  Removing this cost from the project has no effect on the 3.5m run or the replacement of the 1m run.  +Almost $18k was allotted in the budget to run 15 fibers to the dome of the ARC-SAT telescope.  Removing this cost from the project has no effect on the 3.5m run or the replacement of the 1m run.
  
-'''Reduce IFU fiber count to 91'''+**Reduce IFU fiber count to 91**
  
 This reduces the number of elements in the IFU by a little over half.  For a simple hexagonal packed IFU with a 1.4 arc-sec fiber size the long axis of the IFU would be reduced from 37 to 23 arc-seconds.  This still assumes 47 sky fibers terminated in mini bundles around the central IFU. This reduces the number of elements in the IFU by a little over half.  For a simple hexagonal packed IFU with a 1.4 arc-sec fiber size the long axis of the IFU would be reduced from 37 to 23 arc-seconds.  This still assumes 47 sky fibers terminated in mini bundles around the central IFU.
  
-'''Reduce IFU fiber count to 37'''+**Reduce IFU fiber count to 37**
  
 This reduces the number of elements in the IFU by almost a factor of 6.  For a simple hexagonal packed IFU with a 1.4 arc-sec fiber size the long axis of the IFU would be reduced from 37 to 15 arc-seconds.  This still assumes 47 sky fibers terminated in mini bundles around the central IFU. This reduces the number of elements in the IFU by almost a factor of 6.  For a simple hexagonal packed IFU with a 1.4 arc-sec fiber size the long axis of the IFU would be reduced from 37 to 15 arc-seconds.  This still assumes 47 sky fibers terminated in mini bundles around the central IFU.
  
-'''Eliminate Lenslet Coupling'''+**Eliminate Lenslet Coupling**
  
 The primary effect of eliminating the lenslet coupling to the IFU is a reduction in the fill factor.  Coupled IFUs can reach fill factors near unity (~90%).  By switching to a ‘bare’ fiber system the fill factor of the IFU would be reduced to ~38%.  This assumes the f-ratio of the 3.5m telescope is corrected to f/5 which will maintain the 1.4 arc-second spaxal size.  MaNGA has shown that accurate dither patterns will fill in the gaps of bare fiber IFUs so the primary cost is a ~62% reduction in observing efficiency.  There may also be some implications to the data regularity when the dither sets are combined. The primary effect of eliminating the lenslet coupling to the IFU is a reduction in the fill factor.  Coupled IFUs can reach fill factors near unity (~90%).  By switching to a ‘bare’ fiber system the fill factor of the IFU would be reduced to ~38%.  This assumes the f-ratio of the 3.5m telescope is corrected to f/5 which will maintain the 1.4 arc-second spaxal size.  MaNGA has shown that accurate dither patterns will fill in the gaps of bare fiber IFUs so the primary cost is a ~62% reduction in observing efficiency.  There may also be some implications to the data regularity when the dither sets are combined.
  
-'''Bare Bones Option'''+**Bare Bones Option**
  
 This is an option proposed by Bruce to use as much existing infrastructure as possible to join APOGEE to the 3.5 m.  It would involve using existing conduits and would integrate into the Echelle focal plane utilizing the Echelle guider.  I am assuming we would still correct the f-ratio to f/5, which is one of the remaining high cost items in this option.  The two obvious advantages of this system are that it is far cheaper than any other option proposed, and it does not require forest service approval as no modifications to the site is required.  The primary affects are as follows. 1) There is no field rotator on NA1.  So the system would only be available for single object point source work no MOS or IFU mode would be available. 2) Throughput would be reduced due to the longer fiber run an extra ~12% (~10% to ~22%). This is an option proposed by Bruce to use as much existing infrastructure as possible to join APOGEE to the 3.5 m.  It would involve using existing conduits and would integrate into the Echelle focal plane utilizing the Echelle guider.  I am assuming we would still correct the f-ratio to f/5, which is one of the remaining high cost items in this option.  The two obvious advantages of this system are that it is far cheaper than any other option proposed, and it does not require forest service approval as no modifications to the site is required.  The primary affects are as follows. 1) There is no field rotator on NA1.  So the system would only be available for single object point source work no MOS or IFU mode would be available. 2) Throughput would be reduced due to the longer fiber run an extra ~12% (~10% to ~22%).
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 1/20/15 - I've updated the budget for the 'bare bones' option based on input from Mark and Bill - NKM 1/20/15 - I've updated the budget for the 'bare bones' option based on input from Mark and Bill - NKM
  
 +{{medialist>wiki:inst:*}}
  
instruments.1646957492.txt.gz · Last modified: by holtz
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