Does Sauram - the sect of Lord Surya being Supreme Being, still exists? One of my Bengali friends are Saurite. If they are still existing, when did the community got declined? What are their holy books?
Let me add a partial answer because the information i'll be providing is knowledge-worthy.
To be specific,i'm answering this question"Which Hindu Texts describe Surya as the Supreme Being Or are there any such texts at all?".This question is relevant here because such texts only will form the basis of worshiping Surya as the Supreme Deity.
To my knowledge there are two such texts:
1)The Surya Upanishad,a minor Upanishad allied to Atharva Veda.
&2)The Bhavisya Purana,one of the 18 major Puranas.
(In what follows,i'll be adding a few verses and an image from the Surya Upanishad,all of which are taken from a book called "Sukta Sangraha".)
Following are few verses from the above mentioned Upanishad praising Surya as the Supreme Brahaman:
aum atha sūryātharvāṅgirasam vyā̎khyāsyā̱maḥ | brahmā ṟṣih | gāya̍trī chha̱ndaḥ | ādi̍tyo de̱vatā | haṁsa̍ḥ so̱’ham agni nārāyana yu̍ktam bī̱jam | hrille̍khā śa̱ktiḥ | viyadādi sarga saṁyu̍ktaṁ kī̱lakam | catur-vidha puruṣārtha siddhyarthe jape vi̍niyo̱gaḥ || Now we shall expound mantras of Atharva Veda in relation to the Sun: The seer of this Atharva Aṅgirasa
mantra is Brahma, metre Gayatri, Aditya the deity, ‘Hamsas so’ham with Agni and Narayana is the seed,
the power is hrillekha or hrim, the pin is the power in the process of unfolding the sky etc., the application is its use in repetition for winning the four human goals (viz. Dharma, Artha, Kama and Mokṣa).
ṣat-svarārūḍhe̍na bīje̱na ṣaḍa̍ṅgam | ra̱ktāmbu̍ja-saṁsthi̱tam | saptāśva̍- rathi̱nam | hi̍ranya-va̱rṇam | ca̍tur-bhu̱jam | padma-dvayā’bhaya varada ha̱stam kāla-cakra̍ praṇetā̱ram | śrī sūrya nārāya̱ṇam | ya e̍vam ve̱da sa vai brā̎hma̱ṇaḥ || The six limbs consist of the seed with six vowels added. He indeed is a Brahmana who thus knows the golden Surya Narayana seated on the chariot with seven horses, impeller of the time-wheel, having four
arms bearing two lotuses, the others bestowing promise of refuge and boon, set in the red lotus.
sūrya̍ ā̱tmā jaga̍tas-ta̱sthuṣa̍śca | sūryā̱d vai khalvi̱māni̱ bhūtā̍ni̱ jāya̍nte | sūryā̍d ya̱jñah parjanyo̎ ‘nnam ā̱tmā | The Sun is the Self of the world, moving as well as un-moving. From Surya indeed are these creature born, so also the Yajna (Sacrifice), Parjanya (Rains), food and spirit.
nama ̍ste āditya | tvam-e ̱va pra ̱tyak ṣa ̱m karma ̍ kart āsi | tvam-e ̱va pra ̱tyak ṣa ̱m brahm ā ̍si | tvam-e ̱va pra ̱tyak ṣa ̱m vi ṣnu ̍rasi | tvam-e ̱va pra ̱tyak ṣa ̱m rudro ̍’si | tvam-e ̱va pra ̱tyak ṣa ̱m riga ̍si | tvam-e ̱va pra ̱tyak ṣa ̱m yaju ̍rasi | tvam-e ̱va pra ̱tyak ṣa ̱m s ām ā ̍si | tvam-e ̱va pra ̱tyak ṣa ̱m atha ̍rv āsi | tvam-e ̱va sarva ̍m chhando ̱’si | I bow to you Aditya; you are the agent himself of work, the manifest Brahma, Vishnu, Rudra, Rig, Yajur,
Sama, Atharva Vedas, as well as all the chandas (Metres).
ā ̱di ̱ty ād v ā ̍yur j ā ̱yate | ā ̱di ̱ty ād bh ū ̍mir j ā ̱yate | ā ̱di ̱ty ād āpo ̍-j āya ̱nte | ā ̱di ̱ty āj jyoti ̍r j ā ̱yate | ā ̱di ̱ty ād vyoma di śo ̍ j āya ̱nte | ā ̱di ̱ty ād de ̍v ā j āya ̱nte | ā ̱di ̱ty ād ve ̍d ā j āya ̱nte | ā ̱di ̱tyo v ā e ̱ ṣa e ̱tan ma ̱ṇ ḍala ̱ ṁ tapa ̍ti | a ̱s āv ā ̍di ̱tyo bra ̱hm ā | From Aditya are born air, earth, water, fire, sky, directions, Devas, Vedas; indeed the Sun gives warmth to
this sphere (Planet) ; that Sun God is Brahman,
And a few more like:
All creatures are born of Surya and are protected by him, dissolve in him – I am Surya himself. The divine
Savitar is our eye and He is called the Parvata because He indicates Sacred timings through His Timeperiods and let Him protect our eyes.
In this chapter the Trimurthis(Brahma,Vishnu & Mahesh) eulogises the Virata Rupa of Surya.And Surya's worship as "Omkara" is also described.Here Surya is being described as the Supreme Para Brahaman.
At the beginning of Kalpa, Tri Murthis became ictims of �Ahamkaar� (Self-image) and when a gigantic form of luminosity appeared on the Sky, they were taken aback as to how this huge illumination emerged from! As the Great Light approached and dazzled their vision, the personification of Surya Deva in a �Virat Rupa� (Collosal Form) got materialised, the Tri Murthis and Devaganas greeted it again and again with veneration. Lord Brahma eulogized the Virat Swarupa of Surya Deva as follows:
Namastey Deva Devesha Sahasra kiranojjvala, Loka Deepa Namastestu Namastey Konavallabha/ Bhaskaraaya Namo nityam Khakholkaya Namo Namah, Vishnavey Kaalachakraaya Somaayaamita tejasey/ Namastey Pancha Kaalaaya Indraaya Vasuretasey, Khagaaya Lokanathaaya Ekachakra rathaayacha/ Jadvitaya Devaaya Shivaayaamita tejasey, Tamoghnaaya Surupaaya tejasaam nidhaye namh/ Arthaya Kamarupaaya Dharmaayaamita tejasey, Mokshaaya Moksha rupaaya Suryaaya Namo Namah/ Krodhalobha viheenaaya lokaanaam sthith hetavey, Shubhaya Shubharupaaya Shubhadaaya Shubhhaatmaney/ Shantaaya Shantarupaaya Shanatayesmaasu vai namah, Namastey Brahmarupaaya Braahmanaaya namo namah/ Brahma DevaayaBrahmarupaya Brahmaney Paramaatmaney, Brahmanye cha prasaadam cha vai kuru Deva Jatpatey/
(Deva Devesha! Loka Deepa! Kona Vallabha! You are the source of phenominal illumination to the whole World; You are all the Deities like Bhaskara, Vishnu, Kaalachakra, Soma, Kaala, Indra, Vasu, Agni, Khaga, Lokanatha rolled in one as the Ekachakri, bestowing propitiousness and positiveness all over; You are the Embodiment of Dharma, Artha, Kama and Moksha; You are the Personification of Tranquility and Peace, devoid of anger, greed, jealousy and partiality; You are the Parabrahma Himself!)
Similarly Vishnu & Shiva also follow praises Surya with stutis .Trimurti's worship of Surya Deva also included in that chapter.