Author Topic: Give peas a chance!  (Read 312402 times)

Rick Nowell

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Re: Give peas a chance!
« Reply #2910 on: March 23, 2014, 12:04:26 pm »
Why not? As Budgieye once showed, there are red ones as well, which suggests that a more appropriate name for them would be simply Peas.
Hmm ... well, for one thing, it raises the question of what's essential for an extragalactic object to be called a Pea?

If a person looks at an SDSS picture and the Pea Galaxy is green, then it can only be a GP. There are also Pea Galaxies
that have differing colours, but these are simply a photographic representation of an object that, if the person was nearby,
would be blue/white, with perhaps a touch of green.

After I consulted with (Prof.) Bill Keel about the actual nearby colour, we settled on a blue-white colour, perhaps with a hint of green.
After all, they are blue compact dwarfs and not red compact dwarfs.

So GPs can be PGs, but any other colour PGs can't be GPs. GPs and PGs can also be Luminous Compact Galaxies, as GPs, PGs are seen
as a subclass of LCGs. Also, some LCGs, PGs and GPs might well be Extreme Emission Line Galaxies, as well as ordinary ELGs.
Thus GPs, PGs, LCGs, ELGs and EELGs might all be Lyman Break Analogues.

GPs, PGs, LCGs, ELGs, EELGs, LBAs? Context-dependent surely...

Mind you, in Wikipedia, they are in the article 'Pea galaxy'.     http://en.wikipedia.org/wiki/Pea_galaxy
« Last Edit: March 23, 2014, 12:06:37 pm by Rick Nowell »

djj

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Re: Give peas a chance!
« Reply #2911 on: March 23, 2014, 12:36:32 pm »
Thanks, Rick 8)

Rick Nowell

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Re: Give peas a chance!
« Reply #2912 on: March 25, 2014, 11:33:27 am »
Dr Kaviraj writes (via email): "The SWIFT observations of two peas are scheduled for May. Hoping to get some
decent images and spectra. Will keep you posted!"
SWIFT's, or more precisely The Swift Gamma-Ray Burst Mission, primary mission is to observe Gamma-ray bursts
(GRBs). GRBs are the most powerful explosions the Universe has seen since the Big Bang.  http://swift.gsfc.nasa.gov/

"Green pea galaxies and GRB hosts - different evolutionary stages of the same galaxy or different galaxies?"
Authors: 1.Christina Thoene (IAA - CSIC), 2. Ricardo Amorin (IAA - CSIC), 3. Jose M. Vilchez (IAA - CSIC)
http://bama.ua.edu/~rbuta/iau-2012-sps3/program.html
Abstract:
"... Long-duration gamma-ray bursts (GRBs) have been connected to the collapse of very massive stars and
their hosts share a number of properties with GPs (low metallicity, compact dwarf galaxies, elevated star-formation
rate and indications for outflow of gas) although at a somewhat lower star-formation rate. We compare a sample of
low-redshift GRB hosts with GPs in terms of abundance ratios, metallicity and kinematical signs for in-/outflow of gas
and apply stellar population evolution models to investigate whether they could be the same kind of galaxy at different
evolutionary stages."

Unfortunately, I can't find any more info Christina Thoene's poster conribution. I guess wildly that, in a dwarf galaxy
such as a GP, a GRB could be a 'fuse' to spark more star formation? Which is first; a starburst or a GRB?

c_cld

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Re: Give peas a chance!
« Reply #2913 on: March 30, 2014, 09:15:30 am »
Who discovered green peas?

Prior to rediscovery by the Galaxy Zoo project, there was in literature
Metal Abundances of KISS Galaxies. II. Nebular Abundances of Twelve Low-Luminosity Emission-Line Galaxies arXiv:astro-ph/0401131 J. Melbourne, A. Phillips, J. Salzer (8 Jan 2004)

Quote
We present follow-up spectra of 39 emission-line galaxies (ELGs) from the KPNO International Spectroscopic Survey (KISS). Many targets were selected as potentially low metallicity systems based on their absolute B magnitudes and the metallicity-luminosity relation. The spectra, obtained with the Lick 3-m telescope, cover the full optical region from [O II]3726,29 to beyond [S IIl6717,31 and include measurement of [O IIIl4363 in twelve objects. The spectra are presented and tables of the strong line ratios are given. For twelve high signal-to-noise ratio spectra, we determine abundance ratios of oxygen, nitrogen, neon, sulfur and argon. We find these galaxies to be metal deficient with three systems approaching O/H of 1/25th solar. We compare the abundance results from the temperature-based T_e method to the results from the strong-line p_3 method of Pilyguin (2000).

One of the twelve ELGs analysed is
KISSR Field ID Run Q z EW-Hb EW-[OIII] Type
KISSR 2097 F1606 6404 82 1 0.3201  16.21 828.20  SY2

It's a green pea 1237659326026613045 z 0.320 satisfying the ugriz color-cut of http://arxiv.org/pdf/0907.4155
but posted Reply #2887 on: July 31, 2013 after available Boss spectrum.

KISS F1606-6404 , KISSR 2097 (available search names)

I think the Cardamone's paper should have cited the previous work  :-[

Need updating Wikipedia article 'Pea galaxy'  ???

« Last Edit: March 30, 2014, 09:35:19 am by c_cld »

Rick Nowell

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Re: Give peas a chance!
« Reply #2914 on: March 30, 2014, 12:13:50 pm »
Who discovered green peas? Prior to rediscovery by the Galaxy Zoo project, there was in literature
Metal Abundances of KISS Galaxies. II. Nebular Abundances
of Twelve Low-Luminosity Emission-Line Galaxies
arXiv:astro-ph/0401131 J. Melbourne, A. Phillips, J. Salzer (8 Jan 2004)

Melbourne 2004 is cited, along with Melbourne & Salzer 2002, in this interesting 2011 paper:

A nearby GRB host galaxy: VLT/X-shooter observations of HG 031203 by Guseva, N. G.; Izotov, Y. I.; Fricke, K. J.; Henkel, C.
http://arxiv.org/abs/1111.1393 , which has in its abstract:

"This implies that Luminous Compact Galaxies with extreme star-formation that also comprise green pea galaxies as a subclass
may harbour Long-duration Gamma-ray Bursts."   (note GRBs)

As for why it wasn't used in Carie's paper? Best ask her...  Updating Wikipedia? Anyone can!
« Last Edit: March 30, 2014, 02:59:02 pm by Rick Nowell »

c_cld

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Re: Give peas a chance!
« Reply #2915 on: March 31, 2014, 11:02:46 am »
Other preceding paper of Galaxy Zoo Green Peas: Discovery of A Class of Compact Extremely Star-Forming Galaxies but not cited:

A POPULATION OF METAL-POOR GALAXIES WITH ~L* LUMINOSITIES AT INTERMEDIATE REDSHIFTS arXiv:0903.3948v1 [astro-ph.CO] 23 Mar 2009 John J. Salzer, Anna L. Williams, & Caryl Gronwall (Submitted 23 December 2008)

KISS objects showing the ugriz cutouts of green peas and spectra by the 9.2-m Hobby-Eberly Telescope (HET).

SDSS J131549.43+433430.4 1237661850400063541 KISS F1316-5689, KISSR 1516
z spec=0.3277



SDSS J154945.59+430325.5 1237661386539467096 KISS F1549-5609, KISSR 2042
z spec=0.3568



SDSS J160805.18+430207.6 1237659325490200886 KISS F1606-1480, KISSRx 467
z spec=0.0901



Quote from: John J. Salzer et al.
4.1. A New Class of Galaxy?
Given the large number of studies of metal abundances in galaxies with intermediate and high redshift mentioned in the Introduction, it may seem odd that systems similar to those described here have not been recognized previously. Our interpretation of this enigma centers on the fact that the [O III]-selected low-metallicity KISS galaxies are likely to be quite rare. Over the 136.1 deg2 covered by KISS lists included in this study, only 15 such objects were detected.

 ::)

c_cld

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Re: Give peas a chance!
« Reply #2916 on: March 31, 2014, 01:03:47 pm »
Radio Continuum Emission at 1.4 GHz from KISS Emission-Line Galaxies arXiv:astro-ph/0401133 J. Van Duyne, E. Beckerman, J. Salzer et al. (Submitted on 8 Jan 2004)

Green pea posted above:
KISS F1606-6404 , KISSR 2097 1237659326026613045 z  0.321
Chandra X-ray ID= CXO J160550.9+440540   , radio= FIRSTJ160550.9+440539


FIRST cutout:
FIRSTJ160550.9+440539,

1.88 mJy
S1.4GHz  2.21 mJy  (Radio flux density at 1.4GHz )
Sp  2.43 mJy  (1.4GHz peak flux on 5 observations around 1996-08-25 )
 8)

Not reported in RADIO DETECTION OF GREEN PEAS: IMPLICATIONS FOR MAGNETIC FIELDS IN YOUNG GALAXIES arXiv:1110.3312v1 [astro-ph.CO] 14 Oct 2011  where they claim wrongly the first direct
radio detection of Green Peas by VLA FIRST STACKING DETECTION  (stacking due to survey threshold of ∼ 1 mJy).
 :(

« Last Edit: March 31, 2014, 01:54:24 pm by c_cld »

Rick Nowell

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Re: Give peas a chance!
« Reply #2917 on: April 01, 2014, 02:31:23 pm »
Certainly there will have been citations for some of the 80 GPs before the Cardamone 2009 paper. From the 80 starburst
GPs, 36 have no citations in NED, but the remaining 44 do have one or more previous references in NED. The GPs are from
SDSS DR7, so any later data release can't apply. NED doesn't always have every single reference either. Still, it would be
worthwhile to try and find previous references to the 80 starburst GPs, if only to give clarity to the Wikipedia article. So
attached txt file gives a start.

For instance, J. Salzer's 2009 paper:
From SDSS DR10 - SDSS J131549.43+433430.4 1237661850400063541 KISS F1316-5689, KISSR 1516
From SDSS DR7 - http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=588017604151869566

This object is not in Cardamone 2009's 'raw' 251 GPs though. There is not a spectrum from DR7 (or DR10) for this object, so
there won't be a citation for an object that isn't used, even though it might fulfill the colour cut.
« Last Edit: April 01, 2014, 04:01:35 pm by Rick Nowell »

Rick Nowell

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Re: Give peas a chance!
« Reply #2918 on: April 02, 2014, 03:25:37 pm »
What I don't quite know is whether GPs should be star-forming only; i.e. no AGN allowed?

Included sentence in Wiki Description "A GP is purely star-forming, rather than having an Active Galactic Nucleus." for Jean.

Also edited History of Discovery to allow for Salzer 2009. Thanks to Claude (c_cld).
"It would be wrong to assume that the 80 GPs were all new discoveries. Out of the 80 original, 44 GPs have previous citations dated before November 2009 in the NASA Extragalactic Database. The original 80 GPs were part of a sample from SDSS data-release 7 (DR7), but did not include galaxies from other sources. Some of these other sources did include objects that might well have been classed as GPs if they were in the SDSS sample. One example of a paper that demonstrates this is: In April 2009, authors J. J. Salzer, A. L. Williams and C. Gronwall published a paper in the Astrophysical Journal Letters titled "A Population of Metal-Poor Galaxies with ~L* Luminosities at Intermediate Redshifts". In this paper, "new spectroscopy and metallicity estimates for a sample of 15 star-forming galaxies with redshifts in the range 0.29 – 0.42" was presented. These objects were selected using the KPNO International Spectroscopic Survey (KISS). Certainly 3 of these 15 when viewed as objects in SDSS are green (KISSR 1516, KISSR 2042 and KISSRx 467). Indeed, quoting from Salzer et al. 2009, section 4.1, it reads "A New Class of Galaxy? Given the large number of studies of metal abundances in galaxies with intermediate and high redshift mentioned in the Introduction, it may seem odd that systems similar to those described here have not been recognized previously."

https://en.wikipedia.org/wiki/Pea_galaxy
« Last Edit: April 02, 2014, 03:28:10 pm by Rick Nowell »

zutopian

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Re: Give peas a chance!
« Reply #2919 on: June 14, 2014, 05:20:48 am »
green without OIII
588011101034774847

Hi sepos,

nice find. :D You might have noticed that the emission spikes from the chart are not aligned with the dotted lines in the background. The background lines mark the positions at which a certain atomic emission would be located for the given redshift. If not all major emission spikes are aligned with the background lines the automatic redshift determination has gone wrong. We call this a broken or bad chart. Using the redshift tool I would say your object is a pea at z=0.24.
No need to say that it was previously unknown. Congratulations.

I reply to a post from 2008.:
In DR7 its redshift is 0.539, but in DR9 it is 0.237 !
DR7: http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=588011101034774847
DR9: http://skyserver.sdss3.org/dr9/en/tools/explore/obj.asp?id=1237659327100158472


Rick Nowell

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Re: Give peas a chance!
« Reply #2920 on: June 19, 2014, 11:36:46 am »
The two likely Lyman continuum leakers from:
Linking Ly-alpha and Low-Ionization Transitions at Low Optical Depth, 
A. E. Jaskot, M. S. Oey
http://arxiv.org/abs/1406.4413

These two double the number of known LyC leakers in the local universe.

SDSS J121903.98+152608.5
http://skyserver.sdss3.org/dr9/en/tools/explore/obj.asp?id=1237661070336852109 (DR9)

This is also in Verhamme 2014 as 'a good candidate'.

SDSS J081552.00+215623.6
http://skyserver.sdss3.org/dr9/en/tools/explore/obj.asp?id=1237664668421849521 (DR9)



https://en.wikipedia.org/wiki/Pea_galaxy